So does anybody know where I can find say 10 million no 20 million.. no I think 30 million gold will just about cover it.

I was mildly amused to be going broke training at the endgame in MM3 where it took 100k per level but I'm less amused to be already at that level in the mid 50s in MM4-5. I mean I already decided to not train my archer ranger and rogue because of the low funding.. The game then kindly made it even easier by not giving me a training venue that did more than 50.

Then I open up Castle Kalindra and find a training venue that goes to level 100. So off to the bank I go withdraw all my 7 million gold.. hit the training room... and fall short even of getting all 3 guys to level 100! Even with 3 guys not training (still mid 50s levels) and not even able to train them to max (based on xp I had them all over level 120) I still fell short because of money.

Someone tell me there a 100 million gold stash somewhere!

You don't have to train much in order to beat the game, it's even possible to finish with a level 50 party. You will find very big treasures, but money is always harder to get than XP, so act accordingly, if you find a magic lamp wish for gold.

If you want to make money you can get gems and gemstones in the mines on darkside for making expensive armor, after you've mined everything you can pay the god of the mine to make the gems grow again as often as you want. To speed things up you can save before mining to get better random results (5 gemstones are worse than the gems you could have gotten instead, 3 are better than the few gems you would have gotten instead).
Save before having an armor made and reload until you get plate armor to speed things up.
Another way to make some money is buying unenchanted plate armor from merchants and enchant it to amber or so and sell it back.

Another option is leaving your money at the bank and working for a many years until it has quadrupled or so, if you plan doing so you might want to wait until you freed the Queen and got access to the treasure in the basement of the great pyramid so it can quadruple too, stay level 50 until then so you have more money to quadruple.

Keep in mind that it's totally unnecessary, you can beat the game at low level if you have some skill.

Oh I agree. I ended up not training because I wanted to hold off until I could work out when it was needed. After that post I went to Castle Blackfang, with one of the name big bads and apart from multiple enemies every combat ended with my level 74 knight one hit-killing everything (thanks to the 70 odd levels of heroism the cleric added). This went up to and including Count Blackfang himself.

Just seems a shame I've got about 300 levels of untrained skill!