This suggestion, while reasonable to make it, has very little hope of getting implemented.
The answer "in theory:"
The idea of having only one accepted answer is (to encourage) that one answer is created that is comprehensive. So, following the design-philosophy somebody, possibly you, should now go ahead and create one answer (possibly in CW-mode) containing both approaches that then would be accepted.
The answer "in practice:"
At least on MO the above idea is not really followed often, and some might even consider it strange if it were done as described above. What I would suggest you do is you decide in whatever way (perhaps even via tossing a coin) which of the two you accept, and comment on the other one saying that you consider it as equally good but you can only accept one. (Some also do not accept an answer at all in such a case, and possibly comment why they did not.)
Also note that just to express that you found an answer useful you upvote it (which you can do for as many answers as you like). If you could accept multiple answers the "accept" would effectively become a second vote only, and the usefulness of having this is unclear.