I figured out, that when you use the boot_archive which is installed by oi_b151 (at least the textmode) instead of the one from the live-/installcd for a pv guest, the domain panics directly during init, no matter which kernel you are using (the one from livecd or the installed one), the same panic occurs. If you use the boot_archive from livecd it works, no matter which kernel is used.
Additionally there is no difference between xvm 3.4 (osol b134) and my new linux 3.0.1 based xen 4.1, or between 32bit and 64bit kernel/boot_archive.
Panic when using the boot_archive from b151 installation
xl create -c openindiana
Parsing config file openindiana
Daemon running with PID 2634
v4.1.1 chgset 'unavailable'
OpenIndiana Build oi_151 64-bit (illumos a4e1558c0599)
SunOS Release 5.11 - Copyright 1983-2010 Oracle and/or its affiliates.
All rights reserved. Use is subject to license terms.
panic[cpu0]/thread=fffffffffbc609e0: BAD TRAP: type=e (#pf Page fault) rp=fffffffffbcb42d0 addr=fffffe00041ed840
#pf Page fault
Bad kernel fault at addr=0xfffffe00041ed840
pid=0, pc=0xfffffffffb8c03f3, sp=0xfffffffffbcb43c8, eflags=0x10246
cr0: 8005003b<pg,wp,ne,et,ts,mp,pe> cr4: 2660<vmxe,xmme,fxsr,mce,pae>
cr2: fffffe00041ed840
rdi: fffffe00041ed840 rsi: 0 rdx: 10a559273
rcx: 3 r8: 0 r9: ffffff00c6708000
rax: 0 rbx: 10a559273 rbp: fffffffffbcb4460
r10: ffffff00c554b000 r11: ffffff0000000000 r12: 0
r13: 1 r14: fffffe00041ed840 r15: 10a559273
fsb: 200000000 gsb: fffffffffbc61c20 ds: 0
es: 0 fs: 0 gs: 0
trp: e err: 3 rip: fffffffffb8c03f3
cs: e030 rfl: 10246 rsp: fffffffffbcb43c8
ss: e02b
Warning - stack not written to the dump buffer
fffffffffbcb41b0 unix:die+10f ()
fffffffffbcb42c0 unix:trap+17af ()
fffffffffbcb42d0 unix:cmntrap+12b ()
fffffffffbcb4460 unix:atomic_cas_64+3 ()
fffffffffbcb4500 unix:hati_pte_map+18c ()
fffffffffbcb4580 unix:hati_load_common+15d ()
fffffffffbcb4640 unix:hat_devload+198 ()
fffffffffbcb46a0 unix:kmem_override_cache_attrs+be ()
fffffffffbcb4720 unix:i_ddi_mem_alloc+1a4 ()
fffffffffbcb47e0 genunix:ddi_dma_mem_alloc+1a3 ()
fffffffffbcb48a0 unix:xvdi_alloc_ring+d4 ()
fffffffffbcb48f0 xdf:xdf_setstate_init+f5 ()
fffffffffbcb4980 xdf:xdf_attach+387 ()
fffffffffbcb49e0 genunix:devi_attach+80 ()
fffffffffbcb4a10 genunix:attach_node+95 ()
fffffffffbcb4a50 genunix:i_ndi_config_node+c4 ()
fffffffffbcb4a70 genunix:i_ddi_attachchild+40 ()
fffffffffbcb4ab0 genunix:devi_attach_node+ac ()
fffffffffbcb4b10 genunix:ndi_devi_online+c7 ()
fffffffffbcb4bd0 unix:xvdi_create_dev+258 ()
fffffffffbcb4c40 xpvd:xpvd_bus_config+91 ()
fffffffffbcb4cc0 genunix:ndi_devi_config_one+bd ()
fffffffffbcb4d70 genunix:resolve_pathname+19c ()
fffffffffbcb4dd0 genunix:ldi_vp_from_name+ef ()
fffffffffbcb4e40 genunix:ldi_open_by_name+57 ()
fffffffffbcb4ed0 zfs:vdev_disk_read_rootlabel+a0 ()
fffffffffbcb4f20 zfs:spa_generate_rootconf+26 ()
fffffffffbcb4f90 zfs:spa_import_rootpool+31 ()
fffffffffbcb4ff0 zfs:zfs_mountroot+eb ()
fffffffffbcb5010 genunix:fsop_mountroot+1a ()
fffffffffbcb5040 genunix:rootconf+133 ()
fffffffffbcb5080 genunix:vfs_mountroot+63 ()
fffffffffbcb50b0 genunix:main+136 ()
fffffffffbcb50c0 unix:_locore_start+7e ()
skipping system dump - no dump device configured
rebooting...