I had the original memory foam pillows. If I still had them i'd give you them.
Like this:
http://cgi.ebay.co.uk/ws/eBayISAPI....221433&cguid=f1de15e111c0a0aad3538523ffa7f2da
I can't see from this pic whether it is the original smaller one. They seemed start making bigger ones than mine, but the same shape. I think.
I would recommend you get the memory foam pillow shaped pillows (even though I haven't tried them) instead. I gave up on my ones because they fitted nicely if I was sleeping on my back but, like you, I tend to sleep on my side, and sometimes tuck my arm under the pillow too. I found mine too thin to gve the support I would like. Also they were not as long as normal pillows so they did not nearly cover the width of the bed. which seemed an odd thing to do.
If you can't afford the pillow shaped memory foam ones, and they are bloody expensive after all then it's back to trial and error and make a note of what you do buy in case they are good so you can get them again.