Here is a list of HP/Linux references:
Amazon: Mix of HP-UX and Linux solutions as related on http://www.zdnetindia.com/techzone/linuxcentre/stories/42345.html.
NetAge: HP Secure OS for Linux (aka Trusted linux).
Checkpoint: HP Secure OS for Linux (aka Trusted linux).
Side Effects: Port of their software Houdini on Linux.
Nothing Real: Port of their software Shake on Linux.
Boeing: Linux and HP clusters help Boeing R&D reduce costs as related on http://www.hp.com/products1/linux/infolibrary/boeing.html.
ViaWest: a hp/Linux ISP as related on http://www.hp.com/products1/linux/infolibrary/viawest.html.
Israel Aircraft Industry: a hp/Linux performance cluster user as related on http://www.hp.com/products1/linux/infolibrary/israel.html.
SpeedEra: a hp/Linux ISP as related on http://www.hp.com/products1/linux/infolibrary/speedera.html.
Dreamworks: The Shreck movie realised on HP netserver/Linux as related on http://www.zdnet.com/zdnn/stories/news/0,4586,2761566,00.html.
Cern: Performance cluster realised with HP kayak/Linux as related on http://hp-linux.cern.ch.
Viaccess: High availability cluster realised with HP Proliant/Linux as related on http://www.HyPer-Linux.org/HP-HOWTO/Docs/Viaccess.pdf.
Core Products: SAP with HP Netservers/Linux as related on http://www.HyPer-Linux.org/HP-HOWTO/Docs/CoreProducts.pdf.
California Institute of Technology's Center for Advanced Computing Research: TeraGrid project with an Itanium2 cluster on Linux as related on http://www.HyPer-Linux.org/HP-HOWTO/Docs/Caltech.pdf.
Center of Piezoelectrics by Design: Research project with Itanium2 servers on Linux as related on http://www.HyPer-Linux.org/HP-HOWTO/Docs/PiezoelectricDesign_SS.pdf and http://www.HyPer-Linux.org/HP-HOWTO/Docs/CPD_SS_hpVersion_A.pdf.
ESIEE: Gelato program Research project with Itanium2 servers on Linux as related on http://www.HyPer-Linux.org/HP-HOWTO/Docs/ESIEE_GB1.pdf.
National University Singapore: Life Science Research project with Itanium2 servers on Linux as related on http://www.HyPer-Linux.org/HP-HOWTO/Docs/mit_singapore.pdf.
Ohio Supercomputing Center: Life Science Research project with Itanium2 servers on Linux as related on http://www.hp.com/hpinfo/newsroom/press/2002/021021d.html.
Pacific Northwest National Laboratory: High Perfomance Computing Cluster of Itanium2 servers on Linux as related on http://www.HyPer-Linux.org/HP-HOWTO/Docs/PNNL_Cust_Success_f2.pdf.
Rice University: High Perfomance Computing Cluster of Itanium2 servers on Linux as related on http://www.hp.com/hpinfo/newsroom/press/2002/021119e.html.
Samsung Advanced Institute of Technology: Grid Computing with Itanium2 servers on Linux as related on http://www.HyPer-Linux.org/HP-HOWTO/Docs/SAIT_Itanium-Success-Story.pdf.
University of Houston: High Perfomance Computing Cluster of Itanium2 servers on Linux as related on http://www.tlc2.uh.edu/Itanium2.htm.
BP: Seismic Imaging project with Itanium2 servers on Linux as related on http://www.hp.com/hpinfo/newsroom/press/2003/030421a.html.
German Police: Bea Java Application server for crime fightwith Itanium2 servers on Linux as related on http://www.HyPer-Linux.org/HP-HOWTO/Docs/PoliceSaxony.pdf.
Inria Grenoble: High Perfomance Computing Cluster of Itanium2 servers on Linux as related on http://www.HyPer-Linux.org/HP-HOWTO/Docs/Inria2-GB.pdf.
Pittsburgh Supercomputing Center: Grid Computing with Itanium2 servers on Linux as related on http://www.hp.com/hpinfo/newsroom/press/2002/021114c.html.
MIT Laboratory for Nuclear Science: Particles Computing with Ampha servers on Linux as related on http://www.hp.com/techservers/news/news_hpc_18995.html.
Queens University, Belfast: High Perfomance Computing Cluster of Itanium2 servers on Linux as related on http://www.HyPer-Linux.org/HP-HOWTO/Docs/Queens_Success_Story.pdf.
Norwegian University of Science and Technology: Grid Computing with Itanium2 servers on Linux as related on http://www.HyPer-Linux.org/HP-HOWTO/Docs/norway.pdf.
University of Regina, Canada: Computing and simulation with Ampha servers on Linux as related on http://www.HyPer-Linux.org/HP-HOWTO/Docs/success_regina.pdf.
Sandia National Laboratories: Nuclear research with Ampha servers on Linux as related on http://www.HyPer-Linux.org/HP-HOWTO/Docs/success_sandia.pdf.
University of Wuppertal, Germany: The biggest performance cluster in Germany with Ampha servers on Linux as related on http://www.hp.com/techservers/basic_research/success_wuppertal.html.
Boeing: Performance cluster with MSC.Linux as related on http://h30046.www3.hp.com/casestudy.php?topiccode=20020102_Boeing&searchid=0&showpage=&searchtopiccode=LINUXCASESTUDY&pagesite=LINUX®ioncode=&langcode=USENG.