There Are 12 'Table-Top SEMs listed here.  Additional instruments may be added as we become aware of their presence in the marketplace. 

Agilent 8500 FE - Low Voltage FE-SEM

http://cp.literature.agilent.com/litweb/pdf/5990-6183EN.pdf

ASPEX - PSEM eXpress/ EDX

http://www.aspexcorp.com/Solutions/SEMS/ASPEXEXpresstrade.aspx

Aquilla-hybrud SEM (used on the Bio-Bus!!) - TOPCON USA

http://www.topconpositioning.com/sem/product-details/aquila-hybrid-sem

EVEX Tabletop SEM/ EDX

http://www.youtube.com/watch?v=eaLpj1gK0G4

http://actaphysica.com/blog/news/mini-sem-tabletop-scanning-electron-microscope-evex/

http://www.evex.com/Imaging.html

Hirox - Japan, SH-3000 SEM

http://www.hirox-europe.com/products/microscope/indexsem.html

InduSEM - TESCAN USA

http://www.tescan-usa.com/products/indusem.html

LVEM6 - Delong America, Inc. (Chech Republic mfg.)

LVEM5 Low Voltage SEM, STEM, TEM, Electron Diffraction

http://ca.linkedin.com/in/jaredlapkovsky

Overview: http://www.tabletop-em.com/

http://www.lv-em.com/

info@lv-em.com

Nanoeye SNE 3000M Mini SEM - SEC Co., So. Korea

http://www.seceng.co.kr/eng/product/sne-3000m.php

    SEC Mini-Sem + EDS

    SEC Desktop  SNE 1500M/3000M

    SEC Tabletop Mini SEM

http://www.cheaponsale.com/d-p1119096448456010000-table_top_sem_sec_mini_sem_scanning_electron_microscope/

Novelx, Inc. Lafayette, Ca.   

        Agilent (Jan.2010) mySEM USA, Ca.

     http://www.novelx.com,       Jim Rynne  

NeoScope - 

Phenom (formerly FEI, now offered by Phenom World BV, 2010)

http://www.phenom-world.com/products/Phenom-World-desktop-tabletop-SEMphenom.php?referrer=AZOMDOTCOM