The answer is any tablet that runs Windows will run MRSware (and any other normal Windows desktop programs).
There are quite a few out there running Windows, some of which have been around for quite a while. However, they are typically bulkier than the Android and iOS tablets, since Windows needs more horsepower to run. The only thing you need to watch out for is to make sure it is running Windows 7 or Windows 8 -- they have a tablet OS (more like Android or iOS) called Windows RT, which is confusing in naming since it won't actually run any of your Windows desktop applications.
I did a little search for tablets that match what you are looking for, and it turns out Amazon.com has quite a list of them:
Windows 7 tablets
Windows 8 tablets
The Windows 8 ones are newer, of course. You just have to make sure it is Windows 8 "Pro" and not "RT", such as with the Microsoft Surface Pro.
Also, it would be remiss of me to not mention the upcoming MRSware Mobile platform that we are beta-releasing in the next month. This is the version of MRSware that will run in a web browser across a number of tablet and phone platforms, and is optimized for those screen sizes and operating systems. The initial versions will have the most common functional points you would expect -- contacts, calendar, tasks, projects -- and we will be adding more as we go. However, if full functionality is what you want, you are only going to find 100% of the features of MRSware in the existing Windows Desktop Client for a while.
I would be interested to know what you think of the Windows tablets, especially new ones like the Surface Pro, for taking MRSware and your other business applications into the field. And, of course, please let me know if you have any questions that I can help with.