One thing you can count on at any tech trade show is an army of entrepreneurs hawking accessories for whatever the hot product happens to be that year.

For the past few Macworlds — the annual gathering for third-party Apple vendors that Apple (AAPL) no longer deigns to attend — the accessory du jour was the iPhone case.

This year the hot new product is the iPad, and the ground-floor exhibition space of San Fransicso’s Moscone West convention center was chock-a-block with iPad skins, cases, stands and fold-out trays.

We walked the floor Thursday morning and counted 61 different products.

Among the highlights:

• The super shock-absorbing Impact Shield ($39.99), demonstrated on the show floor with hammer and M&Ms that remained miraculously intact.
• The “eco-friendly” LostDog case from France in recycled felt ($85.90) or recycled microfiber ($49.52).
• The soft-silicon Extopad case shaped like a Formula 1 steering wheel. “Great for kids.” $39.95.
• The Swivel Pro series in faux leather and “ballistic nylon” ($49.99 to $69.99) from US+U, which promises to donate 3% of proceeds to charity the first year and 1% more each subsequent year to a cap of 10%.
• The book-like Dodo Case, a bamboo tray sandwiched between two covers made in San Francisco using traditional bookbinding techniques ($59.95 to $64.95).
• Technocel’s leather iPad case and Bluetooth keyboard with built-in mic and speaker for VoIP phone calls ($79.99).
• Music Skins’ protective skins in dozens of pop culture-inspired designs, from Sponge Bob to the Sex Pistols ($25).
• KAE’s Deskstand, which secures your iPad with lock and key to protect it from theft and earthquakes. $70.
• ModulR’s hard-plastic case with four tabs on the back to which you can affix hand straps, shoulder straps, a wall mount or a quick stand. Kits range from $49.99 to $99.99.
• Assero’s front-facing iPad Tech-Pack with a fold-out table for hands-free typing. “Its like a little floating desk for your iPad.” ($129.99).

[Follow Philip Elmer-DeWitt on Twitter @philiped]