SpaceMidget75

This utility will take the full sets of MAME Extras (snaps, titles etc) & ROMS and copy only the ones that exist in your Launch Box database (Arcade.xml) to the folders you've specified. It essentially allows you to keep your complete MAME sets elsewhere and create a smaller subset for use with Launchbox. 
LaunchBox
Although using the Copy ROMS option in the Launchbox importer will physically copy the ROMS based on the filters you've selected it won't currently copy the required parent ROMS too, so some games won't run. It also can't bring over the "official" MAME Extras into Launchbox. CopyMAMEExtras has options to handle both of these.
Lightspeed
Currently Lightspeed does not provide the option to copy only the files needed for the filtered ROM set to a new location. CopyMAMEExtras will also handle this.
To Use for Extras
Browse to Arcade.xml
Browse to the sources for the Extras you want to transfer.
Browse to the target location which will usually be your Launchbox Images and Videos folders for your Arcade Platform.
Tick the types you want to transfer e.g Snaps and Titles.
Tick TEST MODE if you want to just test a transfer without copying.
Click Copy

To Transfer ROMS or required parent ROMS
Browse to the source of your MAME ROMS.
Browse to the target for your MAME ROMS which will be your chosen LaunchBox location for the ROMS.
Browse to the "listxml" MAME xml file (This can be extracted from MAME64.exe but I've included one for .181 in the download)
Tick TEST MODE if you want to just test a transfer without copying.
Click either Copy ROMS or Copy Only Parents
"Copy ROMS" will copy ALL the ROMS listed in Arcade.xml including the required parents.
"Copy Parent ROMS" will only copy the required parent ROMS.

NOTES!!

This was knocked up very quick so forgive any bugs. It works fine for me and there are no delete or move functions in the code so it shouldn't be a problem, but it's best I put the caveat in place.
If you use this with Lightspeed AND use the "Copy ROMS" option of CopyMAMEExtras, you will need to edit the Arcade.xml afterwards and do a find|replace to change to the new folder location.
It's not multi-threaded yet so it will appear unresponsive whilst it works (Sorry!) When it's finished, a log will appear in the large box.