Many of the aftermarket frame suppliers such as TCI and Art Morrison make frames for this car all day, and because they sell so many, they are reasonably price. This and they will make sure the frame is set up for the suspension you wish to run (i.e., Mustang II, rear leafs, IRS, etc.) and usually have the brake master included.

While I think it would be a large amount of greif, the newer Rangers from '98 on use a standard front suspension (no Twin I-Beam). I go with the aftermarket frame if money allows, and if not, box the original and get the suspension 'kits' as listed above.

Good luck!