Since the integration of HD video capabilities in many of the new digital SLR (DSLR) cameras it would seem the days of the 35mm adapter or coming to an end. Some of the 35mm adapter makers have shifted gears to produce accessories to make DSLR more like video cameras. The video capabilities of DSLRs are still in their infancy, but have allowed for the use of 35mm lenses in video to produce some awesome results. The pitfalls are poor audio and it is an awkward design for shooting video(remember it was intended for stills); this has lead to the many accessories you can now purchase for the DSLR. To me the 35mm adapter is not dead, it just has competition and still remains an option. The best thing to do if deciding whether to purchase a 35mm adapter for your camcorder or to buy a DSLR is to decide what your needs are and which one best fulfills your needs. For example, if you need clear audio through the use of an external mic then a DSLR might not be a good option. If you need high resolution still to accompany your video, or you are also in the market for a still camera then DSLR might be your best choice. In the end it really come down to the specifics...both technical specs of the camera (whether DSLR or camcorder) and what you need to do with it.
In the end the HD video incorporated into DSLRs is exciting and new especially for those of use who have striven for more control of depth of field in our work. It creates another option..still not completely ideal, but different. Ultimately I am waiting for the day a consumer grade digital camcorder is produced that produces the results of a shallow depth of field...when that day come I can argue that the 35mm adapter may be on its way out...until then it is still a viable option.