I see your point...Slowhand was a huge influence on George's music and viceversa, and I am sure he can play George's parts just as well. Now, add Julian Lennon (for the voice and physical resemblance to John) and you have yourself a semi-reunion.
Don't forget George's son Dhani (he plays guitar, but I haven't heard him sing).
Eric Clapton, Paul McCartney, Ringo Starr, and Dhani Harrison (along with many others) did play together during a show called "Concert for George." I saw it on PBS and bought the DVD, which is very good. I liked Julian's first CD, but he seems to have disappeared.
Back in 1988 I saw Clapton play and he had Mark Knopfler (sp?) of Dire Straits touring with him and doing back-up vocals and that concert was absolutely incredible!