I really like the Pachymar Magnum recoil pad for the big bangers. I think it's the FP990. Not sure if you can leather wrap it as it is a side vented pad with a lot of compression.

My other favourite for the med/large calibres is the Pachymar Deccelerator. This is a great looking pad that leather wraps quite nicely. A very durable pad as well.

Here is a link to a thread about leather wrapping your own pad:

www.huntamerica.com/wwwthreads/showflat.php?Cat=&Board=UBB8&Number=205060&page=&view=&sb=&o=&fpart=1&vc=1

Both pads are available from Brownells. Their URL is:

www.brownells.com

Good luck.