Here's a design for a combined CCD chamber and cold finger assembly.  It is made from three pieces of machined aluminum (the two top pieces are identical), a clear window from Edmund Optics, a few rubber bands, and a plastic spacer.

The base piece that contains the CCD is dimensioned especially for the 0.25" Sony CCD's as used in the Vesta's and ToUCam Pro's.  With proper re-dimensioning of the depth and width of the slot and the window openings, other CCD's could be accommodated.

The clear window is a 1" diameter Edmund Optics anti-reflective coated window with high transmittance, part # NT46-098 (lists for $11).  If desired, other filters up to 1" diameter could be substituted, such as an IR-blocking filter - Edmund has quite a selection of nice (and expensive!) filters.  The window is held in place with a pair of "siliconey" rubber bands that also provide for an air-tight seal.

In theory, since the CCD chamber is quite small in volume, condensation and frosting shouldn't be a problem because of the small amount of moisture that might be trapped.  Additionally, the relatively large cold surfaces should "attract" the moisture away from the CCD itself.  It remains to be seen whether the outside surface of the window will be susceptible to condensation and frosting.

Here is the plan for machining the base piece:

And here is the plan for machining the two lid pieces:

Update: I successfully used this design in my Cheap-O AstroCam IV (although it was slightly compromised by being consructed with common hand tools vs. proper machining). The compact size, large cold finger plate, and solid construction provides quite efficient and quick cooling of the CCD. However, I couldn't properly test the condensation-not-on-the-window theory because of my desert environment with its attendant low humidity.