I also have odd hands, with lots of windows.
They are normally wide but quite stubby. It's a nightmare getting gloves.
I also had the same problem as you, Tempest.
I found that just by practising I naturally found ways around most of the sleights. Over time it became less and less of a problem. I would even go so far to say that it has benefitted me. I mean, imagine a cardsharp with colosssal, Lurch-like shovel-hands? You would never trust anything he dealt, he could be hiding six or seven decks in there.
Little dinky hands arouse less suspicion I think.
Now I know that's not going to counter any of your frustration, but it's something to bear in mind. It does get easier, there have been no sleights that my hand size has prevented me from doing.
In the meantime however, try learning a few sleights at once: One which is unaffected by hand size and one which is. This way you'll have a new and ready working sleight to use in tricks and another sleight to keep practising in your idle moments. I've found that this helps with a bit of the frustration.
On the subject of using smaller cards, this has been discussed at length on the forum before. Here's just one example:
http://www.talkmagic.co.uk/ftopic18622.php&highlight=
So I'm not going to rant on. But in a word, no.
Mark