Now there's a new kernel floating around, offering 1.8GHz, with another 200Mhz up on offer. The modified kernel can be downloaded from the ever-so-generous XDA forums. But it looks like the peeps over at Android Community have cranked it all the way up to 2GHz, and have some delicious benchmarks and screenshots to prove it.
At 2GHz, the $199 Nexus 7 beats Qualcomm's unreleased quad-core chip. Android Community reports that according to Simms, friends of the site on XDA Developers, that at 2GHz, the Nexus 7 isn't what they'd call "stable". If you want to check it out, take a look for yourself!