Are There Any Good, High Power Solid State Amps?

Here's another suggestion Louis.
Keep your 100 watt tube amp and add 2 self-powered subwoofers like the Vandersteen 2Wq with their high-pass filter. This will relieve your amp from the power-sucking bass frequencies and add 600 watts of power for the 20Hz-80Hz subs. You will find the headroom of your existing amp increase enormously as well as the performance of your existing speakers. Here is a link to The Audio Perfectionist and what Richard Hardesty says about the Vandersteens.http://www.audioperfectionist.com/pages/freejournals.html Click on 'Download Revised Journal #2 Free' and then scroll down several pages till you get to SubWoofers.
Only subs with a high-pass filter will allow your existing amp to gain headroom.

McIntosh MC402...no?

Having owned VR4 Gen III HSE, I believe adding subwoofers would be unnecessary and a mistake.

Buy an amp that drives them properly and you're going to be very happy.

All of the brands that I prefer have already been listed.

However, I highly recommend mono blocks with whatever brand you choose.

Louis1,All the suggestions are good and the list is plentiful.Of course one or two will always get overlooked.
Because you feel a need for more power and to be sure the amp is also a match for your pre.I would suggest that you start a short list with only the amps you are able to audition in your system.This may not be possible if you are buying used but it would safeguard against a costly mistake.