Feature Request for Debugging SQL in PGAdmin3 when SQL contains variables

Originally from SQL Server background, there is one feature that I am
missing and would save developers hours of time.

In SQL Server I could copy sql code out of an application and paste it into
SSMS, declare & assign vars that exist in the sql and run - great debugging
scenario.
e.g. (please note I am rusty and syntax may be incorrect)

declare @x as varchar(10)
set @x = 'abc'
select * from sometable where somefield = @x

It would be amazing if simular functionality could be built into in pgadmin3
(NpgSQL uses : instead of @) where I can just drop my sql (params & all)
into the query window.

I realise you can create pgscript, but it doesn't achieve the above...
Currently I have a peice of sql someone has written that has 3 unique
varibles in it which are used around 7 times each...

I originally posted this question on stack overflow, there doesn't seem to
be a (commercial) competitor that does this either:
http://stackoverflow.com/questions/2959343/debugging-sql-in-pgadmin3-when-sq
l-contains-variables