Tyrant of Discord is pretty good.

Lanzo493,
Have you already looked at Hellkite Tyrant? Especially with Liquimetal Coating, or Mycosynth Lattice as a seriously non-budget option.

Also, some thoughts if you need more ramp:

• Maybe some combo of Infernal Plunge; Desperate Ritual; Pyretic Ritual; Seething Song; Geosurge
  
• Expedition Map for anything, and as a barely-budget option, Solemn Simulacrum for a basic, a dude, and some draw
  
• As a non-budget option, Braid of Fire in insane (though only for Instants or cards with Flash)

And a couple other non-budget options, just in case you haven't already looked at them: Sculpting Steel and Rings of Brighthearth

Oops, forgot to mention: Maybe Scrap Mastery?

I combat the "no board presence" problem by using creatures that leave stuff behind when they enter or leave. Mostly goblins, but there are a few other goodies.

You could also use stuff like Crater Hellion to even things a bit.

I like the Hellkite Tyrant suggestion. I'll add it if I ever manage to get it. I don't especially need mana acceleration because I have a lot of mana rocks for that, which is also why Scrap Mastery would hurt me pretty bad by killing all of my mana. I like the Braid of Fire suggestion because it lets me use Feldon's ability, but it costs too much. I'll trade for it if I see it though. Same goes for Sculpting Steel.

Crater Hellion would kill Feldon, so that's not an option. Rings of Brighthearth is a great card, but it works better with extremely high cost activated abilities and planeswalkers so it wouldn't do very well with Feldon at 5 mana.

I misread the Rings of Brighthearth. It's only 3 mana, first of all. It also will copy Feldon's ability at only 2 mana. If I ever manage to get a copy of it that would be awesome.

I haven't played Feldon, so these are off the top of my head.

Thoughts:

Burnished Hart - costs a lot to pull off, but it's some serious ramping
Scuttling Doom Engine - probably won't have to do this for too many turns
Tuktuk the Explorer - leaves a big body behind
Rukh Egg - even better, because it's not a legend
Summoner's Egg - free creatures are good, especially every turn
Deathrender - ditto
Vicious Shadows - things are going to die anyway
Rite of the Raging Storm - your opponents hitting each other is good for your gameplan
Altar of Dementia - milling yourself seems solid
Goblin Bombardment - not a ton of extra value, but could help with pesky creatures
Spinerock Knoll - cheap stuff!
Valakut, the Molten Pinnacle - sweet late game
Sword of the Animist - solid, if not exciting
Grimoire of the Dead - a bit out of the box, but actually matches up with Feldon amazingly well
Greater Gargadon - sac outlet, plus a huge body to reanimate
Insurrection - often game over, but gains value w/unbounded sac outlets

here are some other suggestions:

Mimic Vat - a way to abuse your opponents creatures also
Mind's Eye - red doesn't have much drawing power
Chancellor of the Forge - a couple recursions of this will make an army of chump blockers

You can also look at my Feldon deck here: Abused by the Cane

That's a lot of suggestions. Deathrender is a great idea, but sadly I never have many cards in my hand because all of red's draw also includes discard so I never have many cards, if creatures, in my hand. I'll certainly try Burnished Hart, Altar of Dementia, and Chancellor of the Forge once I get them. If I had a Mind's Eye it would go straight into this deck. I'd love to give Vicious Shadows a shot but our group is very uncompetitive so there's usually not very many cards in people's hands, except when my friend is using Damia.

Stalking Vengeance is another way to get a benefit from creature death

Second deck I ever built when getting into Magic was a Feldon deck. Love Feldon and love what you've done here! :)