Ralf,
I can't shed any additional light on the licensing requirements, but encourage you to read the following book that is about a transcontinental trip by a deaf pilot in an old C150:
"Flight of the Gin Fizz: Midlife at 4,500 Feet", by Henry Kisor (ISBN: 0465024254)
I think you'll enjoy it, and hope that it may encourage you to pursue your dream.
MLS-12D
P.S. Too bad you're not interested in gliding
... you don't know what fun you're missing!