The current myth TV logo is:
Some higher resolution logo images are available at http://svn.mythtv.org/trac/browser/trunk/mythextras/logos
There have been several requests on the mythtv-users list for the original artwork for the logo (which was based on the old Blue_Theme). The text for this logo is:
An unofficial svg version of the logo created in Inkscape is available here. Please note Firefox 2.0 does not currently support SVG filters (and this image makes extensive use of the SVG Gaussian blur Filter). Support was added in Firefox 3.0.
A png rendering of SVG version of the MythTV logo from Inscape can be found here: