53 year old male here. I believe there are quite a few people in here who haven't got a definite diagnosis yet, myself included. I've been definitly diagnosed with a demyelinating disease, possibly MS, after multiple blood tests, ct and mri scans, a brain biopsy, etc, etc....but unlike you, my issues just started this past February.
Over the past 2 weeks I've had a spinal tap, more blood tests (11 vials taken) evoked potentials (optic, auditory and spinal cord), an opthomology appoinment, chest CT (I don't know why), and a Gallium scan. I'll get the results of this batch of tests next Friday from my GP.
If no definite diagnosis can be made, my next MRI is scheduled in March 2010, and Neuro appointment in May. This latest bunch of tests were orderred by my new Neuro at the UBC MS clinic in BC, Canada, so at least I'm in good hands now.
Good luck to you in your search for answers! Hang in there, and don't be affraid to ask for support from the good people you'll find in here.