Yeah...the IMI do, do a .50 Cal Desert Eagle..I once had teh displeasure of shooting one at a gun club many years back...I was told it was a .38 version...and my 16 year old frame would be fine...it wasnt a .38...and I very nearly lost the thing!
The .50 Cal pistol round, is very potent certainly...only problem, and it is a practical problem, is that in a Desert Eagle, you only get 8 rounds in teh clip...not much good in a fire fight.
As has been stated, teh .50AE and .50BMG are amazingly different.
teh pistol round is around 2 inches long and is pretty much .5 inch all teh way along...and its loaded with pistol powder and a lead bullet.
The .50 BMG, is around 6 inches long in total, with a Copper jacketed bullet and much of teh case is gettig on for .75 inches in diameter, loaded with high power propelant...a massively different round. The .50 BMG would probably be capable of punching through an average wall at 1/2 a mile...teh .50AE would not.
Tell you something frightening...for any of you who hang around in america, wher they let off big rounds for fun...a .22LR (small round) can travel a mile and if your unlucky could still kill you...a .308 Rifle round, like you might find coming ou of a Hunting rifle...can travel for 5-7 miles!