A few words about mesh.
The end result is only as good as the source data allows. And the LOD should closely match the source resolution.
Also, be sure the extents ( the outermost bounds ) of the source data exceed the extents of the end mesh... make sure your source is bigger than the end product. The INF produced from VTBuilder needs to be tweaked a bit to force the destination bounds of the oversized source. Then the mesh will exactly cover the area you need. The most common size for mesh in FSX and FS9 is the LOD5-size. I made LOD7 and LOD 8 mesh for CFS2 that is LOD2 sized, but finer resolution meshes should be LOD5-sized or smaller, as they will be much larger BGL file sizes. The source data needs to be bigger than the destination or you will get gaps in the BGLs.
We still don't have a source of world-wide mesh that is suitable for mesh production over LOD8. SRTM is about as good as it gets, with the CGIAR about the best source available. The newer ASTER GDEM v2 data is unsuitable for mesh as it has hundreds of spikes and pits in most LOD5-sized chunks.
In a nutshell, unless you have a secret source of DEM data, or you are making mesh of the US, then there is no better source of mesh available than the sets I have already made for CFS2. Why reinvent the wheel? And, for CFS2, I seriously doubt you need mesh over LOD7 resolution while you are dog-fighting. If you are just looking for screenshots, or scenery flying, you're better off with FSX or FS9.
Dick