mixtures as outcome variables

Dear R-users,

I have an outcome variable and I'm unsure about how to treat it. Any
advice?

I have spending data for each county in the state of California (N=58).
Each county has been allocated money to spend on any one of the
following four categories: A, B, C, and D.

Each county may spend the money in any way they see fit. This also means
that the county need not spend all the money that was allocated to them.
The data structure looks something like the one below:

COUNTY    A        B       C       D        Total
----------------------------------------------------
alameda  2534221  1555592 2835475  3063249  9988537
alpine   3174     8500    0        45558    55232
amador    0       0        0        0       0
....


The goal is to explain variation in spending patterns, which are
presumably the result of characteristics for each county.

I may treat the problem like a simple linear regression problem for each
category, but by definition, money spent in one category will take away
the amount of money that can be spent in any other category---and each
county is not allocated the same amount of money to spend.

I have constructed proportions of amount spent on each category and have
conducted quasibinomial regression, on each dependent outcome but that
does not seem very convincing to me. 

Would anyone have any advice about how to treat an outcome variable of
this sort?

Thanks for any hints!

Jason

Jason W. Martinez, Gradaute Student
University of California, Riverside
Department of Sociology
E-mail: jmartinez5 at verizon.net