Concatenating variables without having to force a type

[Naatan]

Please consider the following snippet as an example

@box-small: 10px;
@box-large: 100px;

.box(@suffix)
{
  width: ~"@{box-@{suffix}}";
}

div.small
{
  .box(large);
}

This would result in

div.small
{
  width: 100;
}

The way to fix this is by assigning the variables as strings, ie: @box-large: "100px";, but this seems very backwards to me as I would need to assign all my variables as strings and I would limit their usability in other areas (ie. calculations). Is there a way to force the type when the variable is used instead?

In short - any way to make above snippet work as expected without modifying the variable itself?

[lukeapage]

Fixed in 1.3.2