Think I have a fix. Will push a MP:

*** PROFILER RESULTS ***
file_server (/home/dooferlad/dev/license-protection/bigdir/license_protected_downloads/views.py:395)
function called 1 times

         824015 function calls (816173 primitive calls) in 0.786 seconds

   Ordered by: cumulative time, internal time, call count
   List reduced from 985 to 40 due to restriction <40>

   ncalls  tottime  percall  cumtime  percall filename:lineno(function)
        1    0.003    0.003    0.786    0.786 views.py:395(file_server)
        1    0.016    0.016    0.552    0.552 views.py:66(dir_list)
      433    0.004    0.000    0.305    0.001 views.py:223(is_protected)
      434    0.004    0.000    0.290    0.001 buildinfo.py:10(__init__)
      434    0.116    0.000    0.256    0.001 buildinfo.py:122(parseData)
        1    0.000    0.000    0.178    0.178 __init__.py:14(render_to_response)
        1    0.000    0.000    0.177    0.177 loader.py:158(render_to_string)
      433    0.002    0.000    0.173    0.000 models.py:11(all_with_hashes)
[29/May/2013 14:34:26] "GET /sources HTTP/1.1" 200 228034
      2/1    0.000    0.000    0.173    0.173 base.py:136(render)
      3/1    0.000    0.000    0.173    0.173 base.py:133(_render)
   1305/1    0.012    0.000    0.173    0.173 base.py:819(render)
   2190/1    0.002    0.000    0.171    0.171 debug.py:72(render_node)
        1    0.000    0.000    0.171    0.171 loader_tags.py:100(render)
        1    0.000    0.000    0.168    0.168 loader_tags.py:48(render)
        1    0.009    0.009    0.165    0.165 defaulttags.py:131(render)
      433    0.001    0.000    0.155    0.000 query.py:616(filter)
      433    0.002    0.000    0.154    0.000 query.py:630(_filter_or_exclude)
     3468    0.014    0.000    0.109    0.000 debug.py:82(render)
      433    0.002    0.000    0.105    0.000 query.py:853(_clone)
      433    0.009    0.000    0.102    0.000 query.py:235(clone)
   188790    0.087    0.000    0.087    0.000 buildinfo.py:42(_set)
5196/1732    0.018    0.000    0.083    0.000 copy.py:145(deepcopy)
     1302    0.003    0.000    0.056    0.000 defaulttags.py:269(render)
  866/433    0.005    0.000    0.045    0.000 copy.py:234(_deepcopy_tuple)
      433    0.004    0.000    0.044    0.000 query.py:1219(add_q)
     6074    0.009    0.000    0.037    0.000 base.py:568(resolve)
     3509    0.009    0.000    0.036    0.000 functional.py:170(wrapper)
      433    0.008    0.000    0.035    0.000 query.py:1030(add_filter)
      433    0.002    0.000    0.035    0.000 copy.py:306(_reconstruct)
     5196    0.033    0.000    0.035    0.000 copy.py:267(_keep_alive)
   193462    0.032    0.000    0.032    0.000 {method 'strip' of 'str' objects}
        1    0.000    0.000    0.029    0.029 bzr_version.py:10(get_my_bzr_revno)
     4384    0.028    0.000    0.028    0.000 {posix.stat}
        1    0.000    0.000    0.027    0.027 branch.py:177(open)
     4778    0.004    0.000    0.026    0.000 base.py:717(resolve)
        1    0.000    0.000    0.026    0.026 bzrdir.py:1070(open_branch)
        1    0.000    0.000    0.026    0.026 branch.py:1995(open)
     3466    0.008    0.000    0.025    0.000 html.py:32(escape)
   103020    0.025    0.000    0.025    0.000 {isinstance}
        1    0.000    0.000    0.024    0.024 bzrdir.py:549(find_repository)