Glen,
   I see three major errors in your figures compares to my ES.  First of
all, I think $30K for an IFR panel is low, particularly if you plan to
install an autopilot.   If you have a good avionics shop build it for you,
you'll have to pay for their labor.
   Second, you didn't include the cost of wiring up the plane or any of the
many accessories you'll probably want like like nav/strobe lights, fuel
pump, internal rudder bellcrank, etc, each of which cost several hundred
dollars.  It adds up.
   Finally, unless you plan to do all bodywork, paint prep and paint
yourself, the $10K figure for that is also low.  We spent well over 1,000
hours on bodywork alone on my ES and it's still in primer, so we have some
more work to do before taking it in for paint.
   I went way overboard on my plane, but I think you should be able to do
what you want for more like $250K if you're getting some builder's assist,
as you showed in your budget.   For about that much money, you can aviod the
multi-year building hassle, save yourself a lot of headaches and buy Jim
Cameron's brand new ES which he just put on the market (that is if someone
hasn't already snapped it up).  It's done, tested and has a full Apollo IFR
avionics stack.
   If you choose to build yourself, be prepared for cost overruns!
   Good luck,
   Skip Slater
   N540ES