So I have been doing more research and I think Im narrowing it down now. In summary I think:

After a period of no network use, ACPI thinks IRQ 23 isnt needed
ACPI turns off IRQ 23
eth0 times out and wont come back without reboot
ifdown/ifup wont fix it

Jun 21 03:04:07 ppp kernel: [   57.447218] eth0: no IPv6 routers present
Jun 21 04:29:46 ppp kernel: [ 5193.747505] irq 23: nobody cared (try booting with the "irqpoll" option)
Jun 21 04:29:46 ppp kernel: [ 5193.747514] Pid: 0, comm: swapper Tainted: P        2.6.24-19-generic #1
Jun 21 04:29:46 ppp kernel: [ 5193.747516] 
Jun 21 04:29:46 ppp kernel: [ 5193.747517] Call Trace:
Jun 21 04:29:46 ppp kernel: [ 5193.747519]  <IRQ>  [__report_bad_irq+0x1e/0x80] __report_bad_irq+0x1e/0x80
Jun 21 04:29:46 ppp kernel: [ 5193.747550]  [note_interrupt+0x2ad/0x2e0] note_interrupt+0x2ad/0x2e0
Jun 21 04:29:46 ppp kernel: [ 5193.747562]  [handle_fasteoi_irq+0xa1/0x110] handle_fasteoi_irq+0xa1/0x110
Jun 21 04:29:46 ppp kernel: [ 5193.747571]  [do_IRQ+0x7b/0x100] do_IRQ+0x7b/0x100
Jun 21 04:29:46 ppp kernel: [ 5193.747577]  [ret_from_intr+0x0/0x0a] ret_from_intr+0x0/0xa
Jun 21 04:29:46 ppp kernel: [ 5193.747583]  [pci_conf1_read+0x0/0x100] pci_conf1_read+0x0/0x100
Jun 21 04:29:46 ppp kernel: [ 5193.747596]  [__do_softirq+0x60/0xe0] __do_softirq+0x60/0xe0
Jun 21 04:29:46 ppp kernel: [ 5193.747609]  [call_softirq+0x1c/0x30] call_softirq+0x1c/0x30
Jun 21 04:29:46 ppp kernel: [ 5193.747614]  [do_softirq+0x35/0x90] do_softirq+0x35/0x90
Jun 21 04:29:46 ppp kernel: [ 5193.747618]  [irq_exit+0x88/0x90] irq_exit+0x88/0x90
Jun 21 04:29:46 ppp kernel: [ 5193.747621]  [do_IRQ+0x80/0x100] do_IRQ+0x80/0x100
Jun 21 04:29:46 ppp kernel: [ 5193.747624]  [default_idle+0x0/0x40] default_idle+0x0/0x40
Jun 21 04:29:46 ppp kernel: [ 5193.747628]  [default_idle+0x0/0x40] default_idle+0x0/0x40
Jun 21 04:29:46 ppp kernel: [ 5193.747630]  [ret_from_intr+0x0/0x0a] ret_from_intr+0x0/0xa
Jun 21 04:29:46 ppp kernel: [ 5193.747633]  <EOI>  [lapic_next_event+0x0/0x10] lapic_next_event+0x0/0x10
Jun 21 04:29:46 ppp kernel: [ 5193.747648]  [default_idle+0x29/0x40] default_idle+0x29/0x40
Jun 21 04:29:46 ppp kernel: [ 5193.747654]  [cpu_idle+0x6f/0xc0] cpu_idle+0x6f/0xc0
Jun 21 04:29:46 ppp kernel: [ 5193.747662]  [start_kernel+0x2c5/0x350] start_kernel+0x2c5/0x350
Jun 21 04:29:46 ppp kernel: [ 5193.747670]  [x86_64_start_kernel+0x12e/0x140] _sinittext+0x12e/0x140
Jun 21 04:29:46 ppp kernel: [ 5193.747678] 
Jun 21 04:29:46 ppp kernel: [ 5193.747679] handlers:
Jun 21 04:29:46 ppp kernel: [ 5193.747680] [usbcore:usb_hcd_irq+0x0/0x60] (usb_hcd_irq+0x0/0x60 [usbcore])
Jun 21 04:29:46 ppp kernel: [ 5193.747702] [via_rhine:rhine_interrupt+0x0/0x7f0] (rhine_interrupt+0x0/0x7f0 [via_rhine])
Jun 21 04:29:46 ppp kernel: [ 5193.747710] Disabling IRQ #23
Jun 21 04:34:46 ppp kernel: [ 5493.104588] NETDEV WATCHDOG: eth0: transmit timed out
Jun 21 04:34:46 ppp kernel: [ 5493.104738] eth0: Transmit timed out, status 0003, PHY status 786d, resetting...
Jun 21 04:34:46 ppp kernel: [ 5493.105384] eth0: link up, 100Mbps, full-duplex, lpa 0x45E1
Jun 21 05:05:02 ppp kernel: [ 7308.203455] NETDEV WATCHDOG: eth0: transmit timed out
Jun 21 05:05:02 ppp kernel: [ 7308.203606] eth0: Transmit timed out, status 1003, PHY status 786d, resetting...
Jun 21 05:05:02 ppp kernel: [ 7308.204254] eth0: link up, 100Mbps, full-duplex, lpa 0x45E1
Jun 21 05:35:16 ppp kernel: [ 9121.303308] NETDEV WATCHDOG: eth0: transmit timed out
Jun 21 05:35:16 ppp kernel: [ 9121.303457] eth0: Transmit timed out, status 1003, PHY status 786d, resetting...
Jun 21 05:35:16 ppp kernel: [ 9121.304106] eth0: link up, 100Mbps, full-duplex, lpa 0x45E1
Jun 21 06:05:32 ppp kernel: [10936.402170] NETDEV WATCHDOG: eth0: transmit timed out
Jun 21 06:05:32 ppp kernel: [10936.402319] eth0: Transmit timed out, status 0003, PHY status 786d, resetting...
Jun 21 06:05:32 ppp kernel: [10936.402968] eth0: link up, 100Mbps, full-duplex, lpa 0x45E1
Jun 21 06:12:40 ppp kernel: [11364.189787] NETDEV WATCHDOG: eth0: transmit timed out
Jun 21 06:12:40 ppp kernel: [11364.189937] eth0: Transmit timed out, status 0003, PHY status 786d, resetting...
Jun 21 06:12:40 ppp kernel: [11364.190589] eth0: link up, 100Mbps, full-duplex, lpa 0x45E1
Jun 21 06:36:06 ppp kernel: [12769.492097] NETDEV WATCHDOG: eth0: transmit timed out
Jun 21 06:36:06 ppp kernel: [12769.492247] eth0: Transmit timed out, status 0003, PHY status 786d, resetting...
Jun 21 06:36:06 ppp kernel: [12769.492892] eth0: link up, 100Mbps, full-duplex, lpa 0x45E1
Jun 21 07:06:22 ppp kernel: [14584.590959] NETDEV WATCHDOG: eth0: transmit timed out
Jun 21 07:06:22 ppp kernel: [14584.591109] eth0: Transmit timed out, status 0003, PHY status 786d, resetting...
Jun 21 07:06:22 ppp kernel: [14584.591757] eth0: link up, 100Mbps, full-duplex, lpa 0x45E1
Jun 21 07:36:36 ppp kernel: [16397.690817] NETDEV WATCHDOG: eth0: transmit timed out
Jun 21 07:36:36 ppp kernel: [16397.690967] eth0: Transmit timed out, status 0003, PHY status 786d, resetting...
Jun 21 07:36:36 ppp kernel: [16397.691615] eth0: link up, 100Mbps, full-duplex, lpa 0x45E1
Jun 21 08:06:54 ppp kernel: [18214.788695] NETDEV WATCHDOG: eth0: transmit timed out
Jun 21 08:06:54 ppp kernel: [18214.788846] eth0: Transmit timed out, status 0003, PHY status 786d, resetting...
Jun 21 08:06:54 ppp kernel: [18214.789492] eth0: link up, 100Mbps, full-duplex, lpa 0x45E1