One more consideration.

If you are planning to move to Windows 7 32 bits (since you ahve Vista 32bits), the upgrade process from Vista takes a long time, but is very accurate and completely automatic.
I use daily a laptop that I had formatted last to install Vista RC1. It got updated several times, and actually the whole hdd migrated to more powerful laptops three times, and eventually upgraded to Widnows 7 Ultimate when it was released; in spite of all this fiddling, it is fast and nice.
So, if this is your case and your Vista flavor does not allow mirrors, you may consider upgrading to 7 Ultimate first, and then migrade to your new SSD via the mirror trick.

Too bad not going to 64 bits, however, since you're at it. Unfortunately, that means formatting.