Iphone Routes Help

Hi all. I recently implemented an iphone interface to a rails CMS
using an iphone subdomain, since this seems to be the most common way
to do this among rails apps. I didn't think about the implications
this would have on my page caching, however. I'd prefer to
reimplement this with a /iphone or /m suffix to the site. I could do
this in routes.rb via a namespace, but that requires separate
controllers for each namespace. I suppose I could use polymorphism to
keep these special controllers fairly dry, but it still seems like
over-kill. I tried adding an 'iphone/blah' route to match every
'blah' route, but that doesn't seem very dry and the format isn't
persistent. Am I totally overlooking a very simple way to implement
this? Here's some routes, if they might help with an answer:

  map.root :controller => 'page', :action => 'index'
# map.iphone 'iphone/' :controller => 'page', :action =>
'index', :format => 'iphone'
  map.schedule 'schedule', :controller => 'schedule', :action =>
'index'
# map.iphone_schedule 'iphone/schedule', :controller =>
'schedule', :action => 'index', :format => 'iphone'
  map.page ':stub', :controller => 'page', :action => 'show'
# map.iphone_page 'iphone/:stub', :controller => 'page', :action =>
'show', :format => :iphone

Thanks for any suggestions.
-Jeff