I've been playing around with the MoM Tweaker editor, made by I Like Serena over at the RealmsBeyond forum. You can do some pretty fun things with it:

-Increase the total number of spellbooks you can get. I've set mine to 20 for the moment.
-Increase the number of retorts you can get. I've set mine to 7 (just one more than vanilla).
-Alter the number of portal towers that spawn on a map. I decreased mine to 4.
-Change the number and type of ruins that spawn on a map. I increased mine a bit, and made them harder.
-And much, much more!

NOTE: some of these changes require the Tweaker to alter the MoM .exe file, so back it up if that makes you nervous.

This is a link to the Tweaker sub-forum of the MoM forum over at Realms Beyond:

http://realmsbeyond.net/forums/forumdisplay.php?fid=53

You should find what you're looking for there.

A wonderful game editor! Please notice that GOG edition of MoM separates game saves from all the other MoM files. User will need to move the save back to the MoM folder before loading it into the tweaker to prevent crash of the tweaker, the map edit tab in particular.

I love this tool but sadly am not good enough with it yet to figure out how to make permanent changes rather than just altering the current save game.

Me too! Is there a help function, or an instruction manual? I can't even adjust the picks at the start to make my superwizard! I try to change the number, but then it changes back?