I was just about to link you to Hamster Hideout, lol. It's got to be the best hamster website out there. No others compare. Have you signed up on the forum yet?

You could try looking up some German forums, even if you can't speak the language their cages are amazing! Here's a thread on a German-based forum, with pictures of their cages: http://www.das-hamsterforum.de/threa...threadid=61187

As for taming have you checked out the taming guide on HH?:
http://hamsterhideout.com/forum/inde...showtopic=5988

It honestly sounds like Grippo is cage territorial, it is common in dwarf hamsters (usually Russian Campbell dwarf hams) to become territorial. Usually a large cage solves any cage territorial problems, but if they've grown up in small cages they may not get over it quickly and it will take a lot of patience. In the end you need to respect their space and if they don't want you picking them in their cage then you shouldn't do so. Letting them climb into a run-around ball, tube or something that you can lift them out with works well.

The best way to watch hamsters....? Sit there and enjoy, lol. The more you give them to do, the more there is to watch. Wheels, toys, deep bedding to burrow in, sand baths to bath in, food to store, etc. Make it interesting for them and it will be interesting for you guys.

I don't believe there is any transparent bedding, but make sure that the substrate you use is safe. Pine, cedar and other softwood shavings contain phenols that harm the respiratory system. Aspen shavings are safe as aspen is a hardwood. Other safe substrates are paper or paper pulp based. Some brands are Care Fresh, Boxo bedding, Eco bedding, Critter Care, Total Comfort, non-scented Soft Sorbent, etc.

Tanks are awesome for hamsters! I use a 20 gallon long (not high) myself. As long as you have a mesh lid there shouldn't an issue as hamsters don't have enough ammonia in their urine to create a problem in the tank so long as you guys clean it out regularly. With cages the minimum floorspace that I would ever give a hamsters is 360 square inches. Hamsters prefer floor space over height so keep that into consideration when choosing your cage.

I'm assuming that you have your girls housed together, so I would check out this link too: http://hamsterhideout.com/forum/inde...howtopic=24143
It talks about the best ways to house multiple hamsters.

I can't wait for pictures!