A few things to think about
Thought it might be worth posting a few things you`ll have to look at before committing money towards parts.
(a) Confirm the rear axle length. Its not a deal-breaker as most axles can be replaced to give the correct spacing, but it`ll probably affect how big a gear cluster is practical to put on the wheel.
(b) Check the frame clearance to confirm that the tire size you want to use will actually fit. Clearance isn`t just width. There`s those cross tubes for fender mounts too.
(c) Check on the feisability of using your current brakes with a different size rim. Adapter mounts are needed to move the brake post mounting positions to move from a 26in to a 700c rim for rim brakes. Disk brakes aren`t an issue.
Some general info: 29ers aren`t just another 700c wheel. Specifically they are 700c rims laced to mtb hubs and axles which normally have a different axle width than road or hybrids.
The other important difference is the frame. The frame is designed to provide clearance for both a 700c rin AND clearance for a 3.5in tire width.
If you are going to use the bike for commuting, guaranteed you can put 700 x 33c tires on a wheelset and it just fit in most 26in mtb frames. It`l fit because the overall diameter of that combo is virtually identical to a 26 x 2.3 wheel diameter.
Which then leads to the next question: Why do you really want to do this?
If you can fit some Schwalbe Big Apples in your current frame - that would be a lot easier and a nicer rider than a larger rim with a smaller tire. With the current advances in tire technology, rolling resistance really isn`t the issue it used to be.
If you really are after a 29er, ie a Schwalbe 700 x 60c on a 700 rim size -there`s no way it`ll fit in any 26in frame I`ve ever seen myself. But that doesn`t mean you can`t look at another frame. It just means there`s a limit to what you can do with a 26in vintage frame.