Yes is the answer, you make the slider a seperate little lisp that uses (setq fo (open (setq fname (vl-filename-mktemp "" "" ".dcl")) "w")) this writes temporary files in this case your slider dcl.
so max_value = 1000; Becomes (write-line (strcat max_value = " (rtos maxv 2 0) ";" ) fo)
So you need to write-line all the dcl. After using dont forget (vl-file-delete fname)
(if (not slider-dcl)(load "slider dcl"))
(slider-dcl 1000 100 50)
I have Mutil getvals, Multi radio buttons and Multi toggles.lsp they are all user definable writing a dcl to suit.
You can make very complicated dcl also by writing to file.