To all who have responded: Thank you kindly for the wonderful insights and/or food for thought regarding my "sonic quest".
To Mr. Nigel Goodwin: I, too, was skeptical regarding the use of a Varicap diode. As I mentioned in my post, I need a much wider range than I believe is possible with a varicap. Thanks for the heads-up about the Transcendent 2000 - I will certainly research it further. Also, sorry to hear about your illness, but I'm glad you are back in peak form again!
To RadioRon: I'm sure you're right about the ease of using digital techniques, and I suppose they would provide excellent results, however, there's just a certain something, that analog synths possess, a certain fat, funky quality that digital units can't quite seem to reproduce faithfully. Thanks for the tip regarding transconductance amplifiers - I'm not familiar with those particular devices, but I'll be certain to Google them & find out more about them next chance I get. Finally, you suggest using pre-existing components such as the MAX038, and I suppose that would save quite a bit of time and effort, but I'd really like to create something from the "ground up", partly to improve my knowledge of such circuits, and partly because I'm hoping my blind ignorance might actually help me to "stumble across" some interesting or novel new design / sound. I'd really like to come up with something completely unique and different from what's commercially available to date.
Thanks, once again to everyone for their input! You've certainly given me much to think about, and I'll be sure to keep everyone posted as to my progress! A good day to all!