AFAIK, there are no third-party 6× space bars with centred stem available online.
7bit ordered 6× space bars from Signature Plastics in his
Doubleshot Replacements Round 4 group buy. These, however, fit only some Cherry G80-series keyboards (and some very few DIY keyboards) because of the position of the key stem.
If you got one of these and wanted to use them on a keyboard with centred stem, then you would have to cut off the existing stem and glue in another one in the centre.
