No. However, please see Mer. It's an effort by talented members of the community to build updated firmware for the N810 and other older tablets that won't run Maemo 5. It will bring as many of the pieces of Maemo 5 to older tablets as possible. And it's being done with the blessing of Nokia.

I think what Nokia has shown of Maemo 5 thus far looks impressive and promising, and the hardware that comes with it should be quite powerful. I have little doubt that I'll find it awesome. Whether you will though probably depends upon your needs and expectations.