strange tempo

[David Bobroff]

I need to create a tempo marking that would look like this:

\tempo 4 ~ 4. = 53

...if \tempo worked like that.  I was trying to cobble something 
together by creating a markup containing music.  My plan was to print a 
quarter tied to a dotted quarter, move a text script using offset and 
remove the engravers for staff lines, clef, time sig, etc.  I ran into a 
bug that makes this impossible; combining ties or dots with \remove 
Staff_symbol_engraver leads to a segmentation fault.

Help?

-David