I just bought 550 main journal & rod bearings, that just may be luck that the ones I needed were available. Are you saying Honda isn't supplying rings for these?
Honda gasket kits aren't available, but individual gaskets are. I haven't been thrilled with too many of the aftermarket gasket kits, but I've heard some guys say Athena is passable, can't comment.
Please please PLEASE do not buy an Athena gasket kit. With fresh machining on the head and an Athena gasket kit, proper torque etc. etc. my engine poured oil. After a 5 mile ride my left pant leg was soaked. Got to TAS classic and get a Vesrah set, they are usually on back order, but I got mine eventually. After tearing the engine down and removing the Athena set and replacing it with the Vesrah set all oil leakage from the top end stopped. Along with the O-ring set from BryanJ for the oil pump cover, the only leak I have right now is from the drain plug which can be remedied on my next oil change with a new washer.
Piston rings are available from Honda only in standard size, you cannot get oversize pistons or rings from Honda.
Anyway, with all that said - should we start a thread and sticky it to assemble a list of 550 parts we would like to see? We could check Honda part availability and create a list from that. Over time perhaps some members could get the ball rolling on part sourcing and/or production, or we could band together with the most needed parts and contact Honda. Contacting Honda may not result in what we would like to see, but it would be worth a shot, no? It seems a pity that various consumables are not available through Honda. I can understand and appreciate the lack of hard parts, but a lack of certain bearings is unacceptable.
Anyway still, I think if you did a run of studs they would sell, especially for those who will be taking after Paul's build.