Hi!
I believe my problem is of a different nature. I'm running kernel 2.6.27-7.16 (the newest one), so this problem should be solved already a while ago (the fix for the other bug was committed in 2.6.27-7.11) but it isn't as I'm experiencing the effects even now.
Just to check if the fix for the other bug is really working on my setup I did:

$ cat /sys/module/ipw2200/parameters/associate

only to receive:

0

which basically means that the other fix is in effect.
Also my symptoms seem to be a bit different. It seems that the other bug is manifested in dmesg by the line:

ipw2200: Failed to send SYSTEM_CONFIG: Already sending a command.

while I'm not getting any of that. That's how my dmesg looks like:

diabolo@silverfire:~$ dmesg | grep ipw2200
[   18.270057] ipw2200: Intel(R) PRO/Wireless 2200/2915 Network Driver, 1.2.2kmprq
[   18.270063] ipw2200: Copyright(c) 2003-2006 Intel Corporation
[   18.270172] ipw2200 0000:00:09.0: PCI INT A -> GSI 18 (level, low) -> IRQ 18
[   18.270629] ipw2200: Detected Intel PRO/Wireless 2915ABG Network Connection
[   18.270681] firmware: requesting ipw2200-bss.fw
[   22.672880] ipw2200: Detected geography ZZE (13 802.11bg channels, 19 802.11a channels)
[14291.899346] ipw2200: Firmware error detected.  Restarting.
[14292.410705] ipw2200: Firmware error detected.  Restarting.
[30937.291767] ipw2200: Firmware error detected.  Restarting.
[30937.793693] ipw2200: Firmware error detected.  Restarting.
[61218.959440] ipw2200: Firmware error detected.  Restarting.

These firmware related errors are a bit worrying but they don't really seem to be related to this bug as they appear much less frequently then the bug itself. These are today's manifestations of the bug:

diabolo@silverfire:~$ uptime
 21:03:23 up 21:32,  2 users,  load average: 0.44, 0.47, 0.45

diabolo@silverfire:~$ grep deactivating /var/log/syslog
Nov 10 11:36:42 silverfire NetworkManager: <info>  (eth1): deactivating device (reason: 11). 
Nov 10 13:01:22 silverfire NetworkManager: <info>  (eth1): deactivating device (reason: 11). 
Nov 10 16:00:02 silverfire NetworkManager: <info>  (eth1): deactivating device (reason: 11). 
Nov 10 16:05:02 silverfire NetworkManager: <info>  (eth1): deactivating device (reason: 11). 
Nov 10 16:43:22 silverfire NetworkManager: <info>  (eth1): deactivating device (reason: 11). 
Nov 10 16:45:22 silverfire NetworkManager: <info>  (eth1): deactivating device (reason: 11). 
Nov 10 16:49:37 silverfire NetworkManager: <info>  (eth1): deactivating device (reason: 11). 
Nov 10 17:05:57 silverfire NetworkManager: <info>  (eth1): deactivating device (reason: 11). 
Nov 10 17:28:02 silverfire NetworkManager: <info>  (eth1): deactivating device (reason: 11). 
Nov 10 17:31:42 silverfire NetworkManager: <info>  (eth1): deactivating device (reason: 11). 
Nov 10 17:33:42 silverfire NetworkManager: <info>  (eth1): deactivating device (reason: 11). 
Nov 10 17:49:23 silverfire NetworkManager: <info>  (eth1): deactivating device (reason: 11). 
Nov 10 17:54:23 silverfire NetworkManager: <info>  (eth1): deactivating device (reason: 11). 
Nov 10 18:18:43 silverfire NetworkManager: <info>  (eth1): deactivating device (reason: 11). 
Nov 10 18:45:23 silverfire NetworkManager: <info>  (eth1): deactivating device (reason: 11). 
Nov 10 18:47:23 silverfire NetworkManager: <info>  (eth1): deactivating device (reason: 11). 
Nov 10 18:52:43 silverfire NetworkManager: <info>  (eth1): deactivating device (reason: 11). 
Nov 10 18:57:43 silverfire NetworkManager: <info>  (eth1): deactivating device (reason: 11). 
Nov 10 19:00:38 silverfire NetworkManager: <info>  (eth1): deactivating device (reason: 11). 
Nov 10 19:05:23 silverfire NetworkManager: <info>  (eth1): deactivating device (reason: 11). 
Nov 10 19:15:28 silverfire NetworkManager: <info>  (eth1): deactivating device (reason: 11). 
Nov 10 19:48:23 silverfire NetworkManager: <info>  (eth1): deactivating device (reason: 11). 
Nov 10 19:50:24 silverfire NetworkManager: <info>  (eth1): deactivating device (reason: 11). 
Nov 10 19:51:03 silverfire NetworkManager: <info>  (eth1): deactivating device (reason: 11). 
Nov 10 19:52:23 silverfire NetworkManager: <info>  (eth1): deactivating device (reason: 11). 
Nov 10 19:58:03 silverfire NetworkManager: <info>  (eth1): deactivating device (reason: 11). 
Nov 10 20:00:43 silverfire NetworkManager: <info>  (eth1): deactivating device (reason: 11). 
Nov 10 20:01:43 silverfire NetworkManager: <info>  (eth1): deactivating device (reason: 11). 
Nov 10 20:11:03 silverfire NetworkManager: <info>  (eth1): deactivating device (reason: 11). 
Nov 10 20:13:43 silverfire NetworkManager: <info>  (eth1): deactivating device (reason: 11). 
Nov 10 20:21:23 silverfire NetworkManager: <info>  (eth1): deactivating device (reason: 11). 
Nov 10 20:23:27 silverfire NetworkManager: <info>  (eth1): deactivating device (reason: 11). 
Nov 10 20:27:03 silverfire NetworkManager: <info>  (eth1): deactivating device (reason: 11). 
Nov 10 20:28:43 silverfire NetworkManager: <info>  (eth1): deactivating device (reason: 11). 
Nov 10 20:34:03 silverfire NetworkManager: <info>  (eth1): deactivating device (reason: 11). 
Nov 10 20:48:43 silverfire NetworkManager: <info>  (eth1): deactivating device (reason: 11). 
Nov 10 20:55:23 silverfire NetworkManager: <info>  (eth1): deactivating device (reason: 11). 
Nov 10 20:57:23 silverfire NetworkManager: <info>  (eth1): deactivating device (reason: 11). 
Nov 10 21:01:03 silverfire NetworkManager: <info>  (eth1): deactivating device (reason: 11). 

Up till about 15:00 today the computer was seeding a torrent and as you can see during this whole time the bug showed up only twice. After that time there was no constant traffic and the frequency of the bug increased dramatically. This seems to confirm that the bug has something to do with the connection being idle.

Please feel free to let me know what other information I should provide.
Thanks!