Hi Madmezza
I'll try and keep this short as this could get complicated.
RFID tag tend to fit into 2 catagories, near field and far field
Far feild systems can have a range of several metres and use frequencies in the high MHz range (>900MHz). These tend to be active tags (have an internal battery and hence bulky) but there are a few passive systems out there.
Near feild is more common currently and have a range of only a few inches. They work at 13.56MHz or 125KHz an are normally passive, ie the tag is self powered with no battery and hence can be quite small. Car key fobs and pet ID tags are common places where you will find these. Without going into too much detail the range is determined by reader and tag coils size, bigger the coils the longer the range.
Because RFID is a relatively infant technology you may find it difficult to find a source for tags and readers. If you are any good at electronic design you may be a get some cobbled up, if not forget it as there is no off the shelf stuff currently out there. If I do end up getting somewhere this project it will be a personal custom design using components now yet available to the public.
The Dallas I keys are a good product but as you say, you need to physically touch them to a connector. Also you will still need design skills to get it to work as a igniton switch.
If you are still interested in this then get in touch and I'll give you more info.
Andy