As far as the older Bonanza's the 'mfg' support for them is very limited. Of course, that means that the 60 year old planes no longer are supported. From 1957 and on, most everything is avail without too much hassle. While it may be impossible to buy a pre-formed wing leading edge skin from Raytheon, or whomever has the ownership now, it's not that hard to find one in the bone yards around the country. If one wanted a brand new leading edge skin, it could be formed by someone with good Al skills.
Some things on Bos are going to continue to be a problem. Nose bowls, and nose gear doors are a good example. So many planes have been on their belly that the skins for the center section are remade by aftermarket shops, but the nose doors and the formed nose bowl is iffy. Door parts for the old planes are getting iffy too as the door tends to fly away in a gust and get damaged.
All flight controls from SN #6 forward are available and being remade including the formers and stringers inside. All cables, swagings, bearings, seals, shafts, and the like are avail but the nose gear oleo strut is becoming scarce. Since it's so overbuilt, they generally last > 10k hours and landings but if it gets scratched, the best solution is to have it metal sprayed then polished out. Retract bushings and bearings are no problem, and the only hassle on the gear is the sector gear and motor drive gear. Some owners don't keep them lubed well and they can get sloppy, or be damaged on landing if the gear is not locked.
The E series engines are orphans, and they will not be resurrected. The jugs are the same as a O-470J or R and are readily available. Most by now have been welded between the fins of the head, it's very common. Pistons and rings are no issue, but the cam, and cam drive gears are a problem. Undersize bearings are no problem, but some of the acc case stuff can be an issue.
The orig Beech elec prop was a thing of beauty. Flawless in operation, smooth and easy to manage. Sadly, it too has reached it's end of life. There are hoarders out there that keep pitch change bearings and motors for them, and also the blade hub bearings which are quite valuable. I have a pitch bearing that is worth about $3k sitting in my cabinet. The Hartzell CS MV prop is the way to go, but it's quite pricey.
As for the more modern Bonanza, from the M35 onward there's no lack of parts support anywhere. The main issue with the M and later is to have the spar box inspected in detail to manage the spar web cracking issue. Any competent A&P who has seen a Bo before can download the inspection instructions and follow it carefully.
For around $80-100k, I don't think there's anything that one could buy that would beat a S35, or maybe a V35A or B, or even the TC that gets up in the FL numbers and really goes. A 300HP V35-TC will cruise right around 200Kts all day long, or at least for 3-4 hours depending on tanks avail.
