Prepending a string to alternate elements in a Python tuple
There may be other ways to do it, but none that I can think of that stands out as being better than what you wrote.  You could tighten up the code by adhering to PEP 8 naming conventions (use lower_case_with_underscores) and eliminating the variable t.

All I can offer is my condolences for being stuck with this stupid interface.  Note that the first thing that webpy does, as you might expect, is split up the tuple into pairs, using their own utils.group() function.


class application:
    def __init__(self, mapping=(), fvars={}, autoreload=None):
        if autoreload is None:
            autoreload = web.config.get('debug', False)
        self.init_mapping(mapping)
        …

 def init_mapping(self, mapping):
    self.mapping = list(utils.group(mapping, 2))