"I'm looking for L glass only."
Well, that certainly limits your options. Just buy the Canon 100L macro. I does go to 1:1 and the optics are seriously good. If you are really interested in a dedicated macro lens then I have a few other suggestions. The Canon 100L (which I own) has both AF and IS. Virtually all macro shooting is done with manual focus, shallow DOF and with a fixed mount such as a tripod. AF and IS are just not necessary. In fact, you'll have AF turned off for macro.
Here are a few other dedicated superlative macro lenses that you might consider: the Zeiss 100/2 makro, the Leica APO Elmarit100/2.8 R, and the Voigtlander APO-Lanthar 125/2.5 SL. The Leica and Voigtlander are no longer produced and will require an R to EOS adapter but they are legendary macro lenses. The Zeiss 100/2 makro-planar is maybe the best of the current Zeiss glass. I own one and prefer it to the Canon 100L. The primary drawback to the Zeiss is that it goes to 1:2 compared with Canon's 1:1. It's capability to go to f2 will produce wonderful bokeh. Of course, it's all manual all the time. (I'm primarily a Leica M shooter and have a 5D2 for macro and sports.) If you do consider the Zeiss 100/2 - take into consideration that the Canon mount (ZE) version does not have a manual aperture setting while the Nikon (ZF or ZF.2) does have a manual aperture adjustment ring. If you decide to use this lens on a mirrorless camera such as the Ricoh GXR / A12 combo you will want the ZF version. ZF mount lenses work just fine (without the electrical connection) on EOS cameras - but not the other way around. One more thing - I wouldn't bother with a 50 or 60mm macro lens. They put you too close to the subject. 100 to 180 is best. The 180L Canon has a great reputation but it's awfully cumbersome and heavy. The Zeiss or one of the R mount macros are worthy of consideration.