From personal experience with various types of drilling. Yes you can completely gut a DPF easily enough with a long drill and a crow bar and wear a mask, no need for cutting the top out to get to all the internals. I have a used a straight through bypass pipe, a completely gutted Dpf and a gutted DPf where I left the CAT in place. I left the CAT in on the third DPF to try and reduce an acrid smell which seemed to work and also made me feel slightly less guilty.
What I found is that driving around with an empty DPF and no remap resulted in the car attempting a regen and therefore pouring masses of stinking smoke out the back. It would stop for a while if I stopped the engine and then kick in again after a few minutes driving. Very embarrassing, so don't wait long to get the remap done. The only way I found to stop these regens were to have MES in the car and reset the DPF as if it'd been replaced, I got up to 250 miles and no smoking exhaust this way.
GT 3.2 V6 - Q2, KONI FSD & EIBACH PROKIT, GTA REMAP, MICHELLIN PS3's, BMC CDA
159 SW 2.4JTDM TI - ALFATUNED, WIZARD BACK BOXES, KW V3 COILOVERS, NOKIAN WR A3/MICHELLIN PS3, PCA DYNAMICS ALIGNMENT.