If I understand what you're after, you can store the whole LongQuery to a file and then query that - or do a resident load (either can be faster - it depends on exactly what you're doing).
You'd do something like
LongQuery: SELECT * FROM LONGQUERY;
Store LongQuery into [c:\Data\LongQuery.qvd] (qvd);
Drop Table LongQuery;
SmallQuery1: LOAD field1, field2 from [c:\Data\LongQuery.qvd] (qvd) where A=1;
SmallQuery2: LOAD field1, field2 from [c:\Data\LongQuery.qvd] (qvd) where B=1;
or
LongQuery: SELECT * FROM LONGQUERY;
SmallQuery1: LOAD field1, field2 Resident LongQuery where A=1;
SmallQuery2: LOAD field1, field2 Resident LongQuery where B=1;
Drop Table LongQuery;
That said, I'm not sure why you'd do 30 sub queries with the same fields - aren't they possible in one query with multiple filters? In both scenarios above, you'd actually end up with just 1 table "SmallQuery1" as Qlik would automatically concatenate the two tables with the same fields in...
Is that what you're after?
Longer term, best practice would be to split your reload process into two parts - have one file that does the select & store from LONGQUERY and another that does the rest of the processing from the QVD file(s) that this saves out - that way you don't have to re-query LONGQUERY when you're doing dev work on the 30 other queries... this is the beginnings of a multi-tier architecture which is very common in Qlik.