[Acer Iconia A500] Neoprimal:
Interesting, I too can't play 1280x720p High@L4.1 and overall bitrate over 3Mbps.

I'm reproducing your results with all my files that are full 720p High@L4.1, they're all running at an overall bitrate of over 3Mbps.

Oddly enough, here is another that won't play for me:

Format : MPEG-4

Format profile : Base Media

Codec ID : isom

File size : 2.50 GiB

Duration : 1h 55mn

Overall bit rate : 3 089 Kbps

Encoded date : UTC 2010-10-03 15:03:08

Tagged date : UTC 2010-10-03 15:03:08

Video

ID : 1

Format : AVC

Format/Info : Advanced Video Codec

Format profile : High@L4.1

Format settings, CABAC : Yes

Format settings, ReFrames : 4 frames

Codec ID : avc1

Codec ID/Info : Advanced Video Coding

Duration : 1h 55mn

Bit rate mode : Variable

Bit rate : 2 720 Kbps

Maximum bit rate : 24.0 Mbps

Width : 1 280 pixels

Height : 544 pixels

Display aspect ratio : 2.35:1

Frame rate mode : Constant

Frame rate : 23.976 fps

Color space : YUV

Chroma subsampling : 4:2:0

Bit depth : 8 bits

Scan type : Progressive

Bits/(Pixel*Frame) : 0.163

Stream size : 2.20 GiB (88%)

Writing library : x264 core 104 r1677 19df41a

Encoding settings : cabac=1 / ref=4 / deblock=1:0:0 / analyse=0x3:0x113 / me=hex / subme=4 / psy=1 / psy_rd=0.00:0.00 / mixed_ref=0 / me_range=16 / chroma_me=1 / trellis=1 / 8x8dct=1 / cqm=0 / deadzone=21,11 / fast_pskip=1 / chroma_qp_offset=0 / threads=3 / sliced_threads=0 / nr=0 / decimate=1 / interlaced=0 / constrained_intra=0 / bframes=3 / b_pyramid=0 / b_adapt=1 / b_bias=0 / direct=1 / weightb=1 / open_gop=0 / weightp=1 / keyint=250 / keyint_min=23 / scenecut=40 / intra_refresh=0 / rc_lookahead=40 / rc=2pass / mbtree=1 / bitrate=2720 / ratetol=1.0 / qcomp=0.60 / qpmin=10 / qpmax=51 / qpstep=4 / cplxblur=20.0 / qblur=0.5 / ip_ratio=1.40 / aq=1:1.00

Encoded date : UTC 2010-10-03 03:56:21

Tagged date : UTC 2010-10-03 15:06:32

Audio

ID : 2

Format : AAC

Format/Info : Advanced Audio Codec

Format profile : LC

Codec ID : 40

Duration : 1h 55mn

Bit rate mode : Variable

Bit rate : 366 Kbps

Maximum bit rate : 456 Kbps

Channel(s) : 6 channels

Channel positions : Front: L C R, Side: L R, LFE

Sampling rate : 48.0 KHz

Compression mode : Lossy

Stream size : 303 MiB (12%)

Language : English

Encoded date : UTC 2010-10-03 15:06:03

Tagged date : UTC 2010-10-03 15:06:32

yet, this plays:

Format : MPEG-4

Format profile : Base Media

Codec ID : isom

File size : 2.50 GiB

Duration : 2h 4mn

Overall bit rate : 2 871 Kbps

Encoded date : UTC 2010-09-09 00:35:28

Tagged date : UTC 2010-09-09 00:35:28

Video

ID : 1

Format : AVC

Format/Info : Advanced Video Codec

Format profile : High@L4.1

Format settings, CABAC : Yes

Format settings, ReFrames : 4 frames

Codec ID : avc1

Codec ID/Info : Advanced Video Coding

Duration : 2h 4mn

Bit rate mode : Variable

Bit rate : 2 480 Kbps

Maximum bit rate : 14.2 Mbps

Width : 1 280 pixels

Height : 544 pixels

Display aspect ratio : 2.35:1

Frame rate mode : Constant

Frame rate : 23.976 fps

Color space : YUV

Chroma subsampling : 4:2:0

Bit depth : 8 bits

Scan type : Progressive

Bits/(Pixel*Frame) : 0.149

Stream size : 2.16 GiB (86%)

Writing library : x264 core 104 r1677 19df41a

Encoding settings : cabac=1 / ref=4 / deblock=1:0:0 / analyse=0x3:0x113 / me=hex / subme=4 / psy=1 / psy_rd=0.00:0.00 / mixed_ref=0 / me_range=16 / chroma_me=1 / trellis=1 / 8x8dct=1 / cqm=0 / deadzone=21,11 / fast_pskip=1 / chroma_qp_offset=0 / threads=3 / sliced_threads=0 / nr=0 / decimate=1 / interlaced=0 / constrained_intra=0 / bframes=3 / b_pyramid=0 / b_adapt=1 / b_bias=0 / direct=1 / weightb=1 / open_gop=0 / weightp=1 / keyint=250 / keyint_min=23 / scenecut=40 / intra_refresh=0 / rc_lookahead=40 / rc=2pass / mbtree=1 / bitrate=2480 / ratetol=1.0 / qcomp=0.60 / qpmin=10 / qpmax=51 / qpstep=4 / cplxblur=20.0 / qblur=0.5 / ip_ratio=1.40 / aq=1:1.00

Encoded date : UTC 2010-09-08 14:08:51

Tagged date : UTC 2010-09-09 00:40:19

Audio

ID : 2

Format : AAC

Format/Info : Advanced Audio Codec

Format profile : LC

Codec ID : 40

Duration : 2h 4mn

Bit rate mode : Variable

Bit rate : 384 Kbps

Maximum bit rate : 500 Kbps

Channel(s) : 6 channels

Channel positions : Front: L C R, Side: L R, LFE

Sampling rate : 48.0 KHz

Compression mode : Lossy

Stream size : 345 MiB (13%)

Language : English

Encoded date : UTC 2010-09-09 00:39:35

Tagged date : UTC 2010-09-09 00:40:19

If we can spot the major difference(s), we may find the culprit.

Could it be overall bitrate or something else I've missed? Either way, I hope Acer sends an update soon. There's no way our tablet needs to be this picky.