Offhand, I am not sure if this has been added already, but the following values are now supported in thank-you emails:
For "Variations which tell more..." setting:
[%on0%]
[%on1%]
[%on2%]
[%os0%]
[%os1%]
[%os2%]
For "Variants affecting price/weight/..." setting:
[%o1_title%]
[%o2_title%]
[%o3_title%]
[%o1%]
[%o2%]
[%o3%]
You might try putting them in a thank-you page and see if they work there too now? BTW, you can make your SKU value pretty much anything you want, as long/detailed as you want it -- anything you type up to the first "," in a Variants line will be passed as [%sku%], so your Variants configs could have lines like this:
Black Large Pocket T-shirt,20.00,16.00,23,Black,L,Pocket
Black Large Plain T-shirt,20.00,15.00,42,Black,L,No pocket
etc.