Samyang apparently have a new 7.5mm f3.5 fisheye out for m4/3. This is an entirely different design than their 8mm fisheye, and is much smaller and more compact. There are some still image samples on the Lens Tip website, and I have to say that these are some of the best samples I've seen from a fisheye. It looks to have good sharpness across the frame even full open, and a surprising lack of fringing and CA at the edges on high contrast areas. To those not used to the Lens Tip samples it's worth noting that they turn the sharpening right down, so some of their samples initially look a bit softer than other site's sample images. However, if you download them and add PP sharpening you can get a much better idea of the potential.
http://www.lenstip.com/1940-news-Samyang_7.5_mm_f_3.5_UMC_Fish-eye_MFT_-_sample_images.html
I don't know about elsewhere, but in the UK they are now available from eBay and the price is about £270, less than half the price of the Panasonic fisheye in the UK.
http://www.lenstip.com/1940-news-Samyang_7.5_mm_f_3.5_UMC_Fish-eye_MFT_-_sample_images.html
I don't know about elsewhere, but in the UK they are now available from eBay and the price is about £270, less than half the price of the Panasonic fisheye in the UK.