There is no reason that you could not design a carrier which would fit over the cocpit or behind the cockpit. There are a number of carriers which fit on the swim platform, or behind it. I came close to buying a 45 foot trawer this winter, which had a 12 foot RIB with center console and 25 hp outboard, mounted on a SS rack, which fit on 2" sq SS tubing bolted and angle braced to the transom--very much like a trailer hitch. The rack had rollers and a manual winch ( it had an electric winch in the past). The RIB was winched aboard athawartships.
There are also several hyraulic lifts which fit behind swim steps or take the place of a swim step and will carry a large dinghy.
You could fabricate a rack over the outboard, and splash well--and I suspect that this would be far safer and easier to use than the rails over the bow. In any case the dynamics of the boat will change, because of more weight higher and in positions other than where normally carried. Re fabricating a bow pulpit is no big deal--we did this on several boats, to give us walk thru access to a Passeral mounted on the bow (the reason for a Passeral [or gangplank] mounted on the bow, is that the rudder of sailboats is often too deep to get close to a bank or dock where the gang plank would be used.
I think that somehow trying to get a 10" keel, or bottom of the boat, up over a bow pulpit would be extremely difficult and perhaps dangerous. There is also the question of there would be damage to the pulpit. Also the anchor roller position has to be considered, and be certain it does not do damage to the dinghy. If you were to follow that route, I probably would fabricate a new bow pulpit, which was only attatched in the middle by a lower bar, and at the top was rounded at each side--thus attatching a trailer roller between the top parts of the modified pulpit and bringing the rails to each side--and then the keel over the trailer roller. There may be other boaters on this form, who have had heavy dinghies, and used other than davit systems to bring them aboard, but it is not easy to do, without a carefully engineered system.
If you put in long davits to put the PP behind the outboard, it would put more weight aft (sort of a leverage effect--and because of the outboard, the davits would be further aft than on a Ranger 25 tug. You might also have to put some cables from the davits to the back of the cabin house--sounds a bit mesy.
Just some other thoughts to consider.