Hi,
I did another workaround of the needs I think you could have.

Code:
#include <acknex.h>

STRING *str = "";

TEXT *txtLevels =
{
	string = ( "level00", "level01" );
}

TEXT *txtConfigs =
{
	string = (
		" -pal palette.pcx -az 0 -el 60 -sunrgb 58 58 58 -ambrgb 19 19 19  -fog1 100 100 100  -fog2 19 39 100  -fog3 100 19 19 -noportals -hiprec -litmapsonly -writelog -mesh -mergeacross -terralit -tesselate -close -solidsky -nodetail -quiet -supsam -threads 4 -gamma 2.25 -phongangle 120  -lmambient 50  -sizeshaded 236 -litres 0.37 -litcomp 0.20 -litmax 255 -litscale 0.68 -radsubdiv 64 -radbounce 3 -bound 56000 -fat 64  48  8  -narrow 32  32  0"
		" -pal palette.pcx -az 0 -el 60 -sunrgb 58 58 58 -ambrgb 19 19 19  -fog1 100 100 100  -fog2 19 39 100  -fog3 100 19 19 -noportals -hiprec -litmapsonly -writelog -mesh -mergeacross -terralit -tesselate -close -solidsky -nodetail -quiet -supsam -threads 4 -gamma 2.25 -phongangle 120  -lmambient 50  -sizeshaded 236 -litres 0.37 -litcomp 0.20 -litmax 255 -litscale 0.68 -radsubdiv 64 -radbounce 3 -bound 56000 -fat 64  48  8  -narrow 32  32  0"
	);
}

typedef struct
{
	char buffer[6000];
	char *chr;
	long size;
} ENT_BUFFER;

ENT_BUFFER entBuffer;

void entBuffer_startup ()
{
	entBuffer.chr = entBuffer.buffer;
	entBuffer.size = 0;
}

void entBufferLevel ( STRING *_str )
{
	long _size = str_len ( _str );
	memcpy ( entBuffer.chr, _str->chars, _size );
	entBuffer.chr += _size;
	*entBuffer.chr = 13;
	entBuffer.chr ++;
	*entBuffer.chr = 10;
	entBuffer.chr ++;
	entBuffer.size += _size + 2;
}

void entBufferAdd ( char *_chr, long _size )
{
	memcpy ( entBuffer.chr, _chr, _size );
	entBuffer.chr += _size;
	entBuffer.size += _size;
}

void main ()
{
	wait(1);
	var levelIndex = 0;
	for ( ; levelIndex<txtLevels->strings; levelIndex+=1 )
	{
		entBufferLevel ( (txtLevels->pstring)[levelIndex] );
		var entIndex = 0;
		str_cpy ( str, (txtLevels->pstring)[levelIndex] );
		str_cat ( str, ".$$M" );
		char *entityBlock = NULL;
		long size;
		char *buffer0 = file_load ( str, NULL, &size );
		char *buffer = buffer0;
		char *bufferLast = buffer + size;
		for ( ; buffer<buffer0+size; buffer++ )
		{
			if ( *buffer == 123 ) // {
			{
				var pos = str_stri ( buffer, "model" );
				if ( pos )
					if ( pos < 10 )
						entityBlock = buffer;
			}
			if ( entityBlock )
			{
				if ( *buffer == 125 ) // }
				{
					long size2 = 3 + (long)buffer - (long)entityBlock;
					entBufferAdd ( entityBlock, size2 );
					long size3 = size;
					size3 -= (long)buffer - (long)buffer0;
					memcpy ( entityBlock, buffer+3, size3 );
					size -= size2;
					buffer = entityBlock - 1;
					entityBlock = NULL;
				}
			}
		}
		
		file_save ( str, buffer0, size );
		file_load ( NULL, buffer0, &size );
		
		str_cat ( str, (txtConfigs->pstring)[levelIndex] );
		exec_wait  ( "wwmp2wmb.exe", str );
	}
	
	file_save ( "level_entities.txt", entBuffer.buffer, entBuffer.size );
	
	sys_exit ( NULL );
}


It recompiles a list of levels listed on a TEXT struct but with no models and creates a single txt file with the description of the models taken from the $$M files generated by WED. This way you could load empty levels and create just the models that are active instead or removing unactive ones.

Salud!