I hear you re: additional potential points of failure.
What about an "alternate backstay antenna"? This works very well...had one on my boat for 20 years, and have installed many others on client's boats.
Very simple to implement: use insulated s/s lifeline. Put a small loop in each end, using Nicopress sleeves. Hoist the upper end to within 2-3' of the mast, using either a spare halyard or a dedicated halyard. Tie the lower end off to the pushpit on either side of the boat (whichever is best for installation of the tuner under deck). Run a length of GTO-15 cable from the tuner to the lower end of the antenna.
You will still need a good RF ground. The easiest way is usually to run a copper strip from the tuner's ground lug to the nearest bronze thru-hull. There are other strategies which also work well in lieu of this or together with this one. These include wire radials (and the very neatly designed KISS-SSB ground system), the pushpit/lifelines/pulpit complex, s/s rub rails, aluminum toe rails, etc.
Hope this helps,