Scott-- I'm saddened too that the new Cooper LTZ's wouldn't fit. Your tire guy is incorrect in assuring you that it is not your rims; because, IT IS purely your aftermarket rims causing the excessive rubbing. The "combination" of wider 9" rim, different offset from OEM, and different back-spacing from OEM has resulted in the already taller 31.4" O.D. and wider 285 series Cooper LTZ tire being spread-out too wide and creating a much wider turning arc when turned.
The "ONLY" reason VX-KAT had no problems is because she used her stock OEM 18x7 rims which kept the LTZ's neatly tucked within the front wheel wells without any major rubbing issues (just a little trim). The use of VX stock OEM rims (1999-16" or 2000/2001-18") is truly "the secret" to minimizing front tire rubbing issues.
I see by your Photo Gallery that your current Nitto T.G.'s are 255/55R18 (29" O.D.). I assume you would like to go a bit wider with a 285 series tire. However; since you have a wide 9" rim, you will need to go with a lower profile (aspect ratio) tire in either a 50 or 55 series low profile to prevent rubbing issues.
I suggest you seriously consider the MAXXIS - MA-S1 MARAUDER tire in either 285/50R18 (29.2" O.D.) or 285/55R18 (30" O.D.). This is a very wicked looking directional tire with a good meaty tread comparable to an A/T type tire and capable of handling snow. Visit
www.MaxxisTires.com. Since your OEM tires were 29.5" O.D., your speedometer will be very close to accurate within 1 to 2 MPH (+/-). Other tire websites you should check-out are
www.1010Tires.com (my personal favorite), and
www.OnLineTires.com.