I've read that about a couple of setups that are in the 300-500 watt range, but as you mentioned, those aren't going to pull me up much of a steep grade.

But either way, it looks like i'll probably have to do to a gearless setup.

I've been kicking this around for a good year now, and I think i'm just going to have to throw my hat into the ring with an established kit maker, and i'm leaning towards the hi-powercycle guys.
And unfortunately their site says they have a 2-4 week lead time.
I wish I had gotten in gear on this earlier this year.