I've purchased two
Adesso WKB-3000UB keyboards - they came with slightly different key assemblies, as-in layout revisions. They have the best mouse button arrangement, in my opinion. It is the same arrangement that has been copied/used by countless other similar keyboards: trackball and L-click trigger on the right "hand grip", and L/R-click and scroll wheel on the left "grip". When you hold the keyboard, these mouse controls are exactly where you fingers expect them.
The downside to most of these mini keyboards is that the membrane keys are not cleanable or repairable. The reason I have 2 of these is that the 1st one has a whole region of the keyboard that quit working. Everything around the "L" key, including the Enter button is dead. The 2nd keyboard I bought has so far outlast the original 3x.
Sadly, the 3000UB is no longer made. And the replacement model# WKB-3000U is inferior in many ways.
[EDIT]
This SIIG keyboard is similar to my Adesso's:
http://www.newegg.com/Product/Product.a ... 6823191009