<warning - waffle ahead!!!>
Speaking as someone who has a little experience with Lambo doors! I'd say that it is possible, but you'll need to have access to a disk cutter, welder, lots of odds-n-sods of Steel off-cut, a good imagination and a lot of patience
I think the most interesting/tricky part would be sourcing and mounting the hinge correctly!
You could always opt for a replica Lambo hinge, or there are other after-market hinges out there that bring your doors out-n-up.
Mounting that on your car and more importantly getting the doors opening and closing without any parts hitting any others parts (please don't underestimate how frustrating this part is!!) will be interesting. As even on my Countach where the car was designed to have these doors, it's still a major faff to get set up right.
Not impossible.
Just a faff!
Choosing and mounting the gas rams is probably the cheapest and easiest part, as long as you've got a welder.
Strikers and door locks are an old Mercedes item and come up on e-bay all the time and again in your case would you would probably need your doors cutting, reinforcing and welding.
Hooking up solenoids & door poppers would be one option so that you don't have to connect them to your existing handles. Or you can go wild with bent bits of metal inside the doors
It's probably worth you having a look over on the Countach/Diablo build threads over on the LamboReplica forums for some more inspiration. Or look around the max-power scene (if they're still going?) as a few years ago they were fitting Lambo-doors to everything
Good luck if you do try it and don't say i didn't warn you about the getting-things-aligned bit
Dave