My first answer doesn't exactly solve your problem but perhaps you could consider it. You can turn down the soft tab spacing to 2 spaces to be able to do what you mentioned in that example. Unless you have a very complicated spacing scheme, I find that 2 spaces gives the best compromise between nicely indented code and control over text placement. This setting would hold for each other language that you don't manually set the soft tabs for.
If you really want no soft tabs at all, the method would be to set a soft tab size of 1, which is not possible in the TextMate GUI. This can be done by modifying the TextMate plist file at the Terminal. You'll need to set that for each language separately. As an example, for Perl:
defaults write com.macromates.textmate OakTextViewScopedTabSize -dict-add 'source.perl' '{ tabSize = 1; }'
Replace source.perl with whatever language you want to use; tabSize = 1 refers to the soft tab size. If it's for plain text, replace source.perl with text.plain. Looking at the com.macromates.textmate plist file, there also seem to be the entries text.catch-all and source.catch-all which I would assume would work for everything that hasn't already been specified. But it didn't seem that way when I tested.
