seems like you'll need a router that doesn't handle NAT for ftp connections..or at least has an option to turn it off..
as for specific model i have no idea..
if people here won't be able to tell you, you could try
www.dslreports.com hardware forum. they've seen many different routers so they might know..
maybe cheapest, simplest router that has absolutly basic NAT w/o "fancy" ftp screwup features is the way to go
