http://www.yescomusa.com/product.php...&cat=91&page=1
http://www.ev-power.eu/?p=productsMo...20ahb-12v-20ah
http://www.a123rc.com/goods-468-Exci...TIC+CELLS.html
http://www.a123rc.com/goods-389-48V+...it+-+Reay.html
Yes there are a couple of ways to go for a reasonable E-Bike, but the real cost now is in the battery system used to power it. Most will go cheaply with some R/C Lipos just because it will save money up front. I am looking at the Prismatic cells, but for a 48volt setup that will be about $1000 just for the battery cells.