Well, lots of vendor replies so far, and, expectedly, each vendor knows their solution to be superior to the others.
There've been a number of threads on this and there are a number of options.
A couple of the vendors used to offer kits made from the stock GTP arms already kitted for the SHO application, but that doesn't look to be available any more (that I can find at the moment). A trip to a junkyard, or a GM parts supplier still makes that a good option. SHOnut still sells the sleeve kits to make this easier. This is arguably the least expensive route to getting adjustable arms on a SHO. The stock GTP arms have compliant bushings (rubber, I assume), and the adjuster and locknuts are mounted close to one end, so they can be accessed easily during alignments.
BMR has the GTP aftermarket arms, which you can get from them and use SHOnut's sleeve kits or just request them with the appropriate bushing diameter (which they've done in the past at no extra cost). I have two sets of these (one on the silver car and one on the Pumpkin) and am quite happy with them. They have greasable poly bushings at both ends and the adjusters and lock nuts are mounted close to one end.
FPS has the already mentioned their aluminum arms. Some folks that have installed these like them, they're plenty strong and will work well. Potential downsides: the Heim joints are subject to corrosion in rust belt areas, the cast iron rear spindles and the torque box need to be drilled out to accomodate the 1/2" hardware used on these, and on each arm one of the locknuts is near the torque box. If you do adjustments with the car on the ground you'll need _really_ long arms to access these.
Long ago TCE used to make adjustable arms that are considered by some to be the best. Todd hasn't made these for years and keeps swearing that he's not going to make any more, so this is only an option if you can find a used set for sale, which doesn't happen very often.
SHObros has already indicated that they'll have something available, but until they do the above is what you get to pick from.
