Valuelist by calculation is a long existing item on my wishlist...
For this problem I use a menu plug-in. I create a popup-menu which displays whatever I want. Also it looks better then the 1990 FM look.
Dacon's MenuControl will do the job. It will cost you some money.
This is a long standing item on my wish list also, but it's also good to avoid plug ins when possible. Once you invest in a plug in, you run the risk that it will not be compatible with a future release of FileMaker that keeps you from upgrading your system until the plug in developer releases an update. If the plug in developer has since gone out of business... Of course, it isn't always possible to avoid that plug in.
If you have a single field value list, (not an ID number if field 1 and a name in field 2, for example), then this method works for modest sized value lists:
Add a number field, SortKey, to your table of values to specifiy the order of the item in the value list.
Add this calculation field, cSpaces, to your table:
Substitute ( 10^SortKey - 1 ; 9 ; " " )
In your value list, specify cSpaces as the Field 2 value and set the value list to sort on this field.
Definitely a major Kludge, but it works for value lists that aren't too large and can avoid having to add a plug in to your solution.