
My own view as a long term Bronica user is that I want to have a spare kit of most of the major bits. You could be as well off selling your body and buying another with a wlf included. Piecing together a kit from bits is not a guarantee of spending less or a recipe for an easy life. So the best way to find a wlf ( or a crank) is to buy a camera with them in place and that is by no means difficult. You need to ask what dioptre they have fitted in the magnifier since these are user interchangeable and its important that you can see well through it. WLF do sometimes come up in the UK and tend to sell for the equivalent of maybe $80-$100. Same with 220 backs and Speedgrips - rarely supplied with a camera, now relatively easy and cheap to find. Both of these are fairly scarce used whereas the prisms were almost always bought separately as accessories and are often sold as such. The Bronica wlf came as part of the kit, and tends to be sold on with the camera body. PS: I am not affiliated with any of these dealers/sellers - just passing on information that might help. I have a Bronica SQ with a metered prism and have often desired for a WLF, but I am not willing to pay the prices they seem to be going at simply because I do not really need it. (I think they are somehow affiliated with "shutterblade" on eBay.)

Another website for Bronica SQ gear is here. They also have other Bronica SQ gear and might be able to find you what you need, in case you decide to go with Bronica. Also, Koh's Camera has a SQ-AI (with a 80mm PS lens, a 120 Back and a WLF) in Mint- condition for $590.00. Please do not be discouraged - there are lots of Bronica SQ gear available on eBay. However, it seems like you have to be willing to pay a bit for these - they seem to be going at a premium these days.

However, I have seen these items from this seller in the past and if you keep an eye on their auctions, you might chance upon one. Those auctions are completed, and as jstraw mentioned, both WLFs went for pretty good prices. Sorry, I couldn't provide the link earlier.
