I guess you could try using includes and macros. Divide the thing into two files: one include file, which will contain the map code, and one (or more) files defining macros and including the map code.

For example:
map.inc
Code:
Type TMap = class
   { snip }
   Procedure Insert(Key: KEYTYPE ; Val : VALUETYPE );  
   Function Search(Key: KEYTYPE ): VALUETYPE ;
   { snip }
map_blocks.pas
Code:
unit map_blocks;

{$MACRO ON} {$DEFINE KEYTYPE:=TMyCoord} {$DEFINE VALUETYPE:=TMyBlock}

{$INCLUDE map.inc}