Luckily I managed to convert these to VGA with few simle steps, which I want to share with the community as a little contribution from my side.
What you need to have:
1. M2D VGA pre-istalled in your device
2. QVGA theme "zip" file (Any M2D theme you want to convert in VGA)
3. Throttle Theme Rescale Tool (Attached)
(Please note that this useful tool is developed by APBilbo for throttle launcher & it works perfect for any theme as it accurately resizes the PNG files from QVGA to VGA. So all credit for this goes to him)
4. HTCHomesettings.xml for VGA (attached)
What you need to do :
1. Unzip the QVGA theme content in a new folder
2. Use theme rescaling tool on this new folder. This will resize all PNG file in this folder to fit your VGA screen.
3. Replace the HTCHome settings.xml file in the folder with the one attached.
4. Zip the folder & copy in your device
5. Add and install the theme with M2DC
------------You are done ! Enjoy the theme of your choice -----------------
Note : The 3rd attachment is a beautiful theme converted from QVGA to VGA which you can directly install & check before you start converting other themes. All credit for this theme goes to the designer of the original QVGA theme.