[Joe]

If anyone is thinking about a macro lens the Tamron f/2.5 Adaptall lens is a way better performer than the later f/2.8 version.
Tamron origianally developed an Adaptall 2 mount in the canon EF mount type to fit all eos cameras. However, the true Tamron original items are seriuosly rare items to come by....they were only stocked by Tamron to cater for their 350mm and 500mm mirror lenses.
Hwoever, there now appaers to be loads of after market pattern made mounts on ebay coming from overseas. Great items, and for only about £20 a bargain to boot.
Two minor critisisms people should be aware of tho...I bought one of the after market items not so long ago and it was a little 'sloppy' on the lenses and camera body...not a major worry, just a little off putting if you're use to quality.....particularly where you might be fitting a heavy lens to a larger SLR.
Second critisism...which also applies to Tamron's own mount when it was available.....your chosen Tamron lens will only have a completely manual aperture/iris operation. Takes a bit of getting use to focusing at open aperture f/2.5 then stopping down as desired.....could be a pain if you're doing shots requiring quick operation?!

Aside from using Tamron adaptall2 lenses....why not try Contax mount lenses...if you've got the cash a good carl zeiss lens will deliver some nice results....and contax lens to canon eos /EF body mount adapters are available for a few pounds....for a few extra pounds (about £40) you can even buy them with a facility to provide focus confirmation in your canon camera viewfinder!