Some sites you might check out:
1)
http://www.elitesimbuilders.com/Forum/index.phpScroll down to the Victorian and also the Mansions parts of the 'Residential Lots' listings. And that site is closing on Aug. 31, BTW.
2)
http://teharimmosims.free.fr/In French, but easy enough to navigate. Houses are grouped by style under 'Les Maisons.'
There's another site which has lots of Italian-type villas, but can't remember the name this minute. Will edit this post and add the link when I can dig it out.
Fianlly had an opportunity to look it up.
3)
http://www.webalice.it/mikebur50/index.htmlIn Italian, but easy to navigate. The first 7 categories to the right of the word Home in the bar near the top are all houses.
Also a couple more which might have something close to what you want that is readily modifiable:
4)
http://www.styling-home.de.vu/5)
http://lsre.jillyann.com/Looking for an already built 4-car garage is rather limiting, but adding on or expanding a garage within a lot isn't all that difficult to do.