Nikon user buys Canon 65MPE - Now a body???

I am a Nikon user (D700 at present). I do a fair amount of macro work. I have been interested in the specification of the Canon 65mm MPE lens for some time and yesterday, I had the opportunity to purchase a used one of these at a steal of a price. I don’t normally do impulse purchases, but the deed is done! Now, I know what you’re thinking, where do I go from here with my current Nikon setup.

I am considering getting a Canon body for this lens and dedicate it as a specialist macro setup, keeping my Nikon gear of several lenses, flash, etc. for general work. Otherwise it’s go the whole hog and change all to Canon. (quite a drastic move )

I am very familiar with the Nikon range and its use and I am an experienced photographer. I am now mulling over which Canon body to go with this lens: full frame (which I use in Nikon at present) 5Dll or the newer 7D which will give a tad more reach with the 65mm or maybe something else?

I could regret running two camera systems side by side, but as I said, I have bought this lens for a specific use. Anyway, you Canon users have any advice you can offer?