There are so many replica Featherbed frames being made these days and not all of them are made to the orginal specs, I am lucky I have both orginal Wideline and Slimline frames but you can easely pick a genune frame from a replica frame on the orginal Featherbed they are a heavy frame but the cubing is very soft and is easely dinted, replicas are nomly a bit lighter and made of harder steel.
I have seen new replica frames going for between $2,000/$2,500 here and some cases more, there are some good built ones around but there are also the ones that don't even come close to being a Featherbed frame so you have to be very carefull when looking for a replica.
If you go for a orginal frame they also have their own problems and the biggest is rust inside the frame and how they have been stored, moister is one of the big killers of Featherbed frames and is usualy on the bottom rails that suffer from rust.
Many years ago my cousin up in Mareeba had a engerning mate who was building Wideline frames to mount up BSA singles, my cousin had one they were both members of a BSA club and he was building a few frames for other club members, It was hard for me to pick much diffrents from a orginal frame to his frames, he builds them the exact way the orginals were made, he had 2 BSA/Featherbeds one for road racing and one for the road, I got the chance to ride his road BSA it was supa light and handled pretty good but to me was missing that power a hot Commando engine has.
My own opinion would be to look for a good orginal Featherbed frame one that has no rust inside the frame, the only diffrents with a Wideline to a Slimeline is how far you like your legs spread apart when riding, I am 5'8" and the Wideline is very comfrotable for all day riding but I do have a comfortable innerstate seat, the Slimeline frames of course the knees are tucked in closer so if your a short person then a Slimeline be better for you, but if your taller then 5'7" then a Wideline is the go, both frames handle the same its all depends on what you want, myself perferr the Wideline frame, but hey I have been riding it for over 35 years now and can't wait to get back into rebuilding the 1960 Manxman caferacer rebuild that I started about 3 years ago, but its being built with a hot 650 motor that came with the box parts, the motor is not the orginal motor that came with the frame the numbers are out by 72 as this Slimline use to be raced, so don't have much orginal Manxman parts for this build, most things have been replaced with alloy (fuel tank, oil tank, wheels and a racing Lucas maggie) so all up it has some good mods but would cost to much to make it orginal again, I am building this one up for my young daughter, lucky girl.
Ashley