Just have Mail open in Rosetta, that's what I've done. Thing is, I only have 512MB RAM, and it doesn't feel much slower than when I ran it in Universal mode.
Make Mail run in Rosetta... it's well worth the extra second or two in load times to be able to check Hotmail within Mail.
Also, if it's worth anything, I have read that newer accounts, in the last two years or so, may not work with httpmail. Keep that in mind if Rosetta doesn't make it work.